Atmospheric sounding requires high-resolution spectrometers, such as Fourier transform interferometers. Classical ones need moving mirrors to scan the spectrum, but static interferometers with stepped mirrors can achieve high resolution in within a narrow spectral band. CNES is developing such an instrument for CO₂ flow monitoring. The breadboard includes two stepped mirrors, a separating plate, a double imaging system and a detector array. To simulate the actual instrument response, we developed a physically realistic model of the full optical system with ASAP, a software well suited for broad sources, partial coherence and non-sequential propagation. After checking the theoretical interferogram and the resulting instrument spectral response for a point source, we simulated the effects of field, coherence length and chromatism. Then we studied the complex ghost reflections between the mirrors, the separating plate, the optics and the detector, taking coherence into account. Resulting interferograms and spectra were compared to the nominal ones. It appears that the most critical ghosts are not the most intense but the best focused, especially when interfering with the nominal waves. Scatter is tolerable, as it is incoherent and relatively uniform. These results led to design improvements and alignment requirements on the breadboard. This study illustrates how physical modeling can contribute to the early design of complex, non-imaging systems.

We report the comparison between two methods to evaluate optical systems. The flux-tracing method is an extension of the classical ray-tracing methods with additional energetic features. The direct integration method involves the calculation of the integral appearing in the diffraction theory of aberrations. We give a brief outline of the two methods and compare the results on a standard optical system. This will help to put in common the two methods to try to formulate new algorithms for the design of optical systems.

The Computer Aided Design, Manufacturing and Engineering world has gradually welcomed simulation tools enabling the modeling of machining, thermal effects, mechanical, dynamic-motion, vibration and acoustic phenomena... but not optical simulation which has evolved independently from the CAD environment. The innovation presented here with SPEOS CAA V5 Based software integrated in CATIA and ENOVIA DMU V5 software from Dassault Systèmes, the premier global PLM solutions provider, is the first optical simulation solution connecting optics to the CAD/CAM/CAE world, and directly impacts and improve the optical design analysis and process. The optical properties are added directly within the software, sharing the same data for mechanical and optical analysis and thus avoiding all the transfer errors. This new approach improves the quality process and allows unlimited detailed mechanical parts used to be used for the simulation. All the geometric transformations and optical properties modifications are done interactively, helping the user to understand the way the photons are propagated in the whole system. New functions available in CATIA/ENOVIA V5 are light emission simulation, light/surface interaction and scattering, light/matter propagation producing optical performance, photometric measurements and stray light analysis. The early integration of optical performances means that a solution can be found faster that will globally fit to all the specifications. This new technology is opening new links with stress effects, thermal effects, mobile and motorized systems, ... during the design of an optical system, giving the ability to evaluate optical performance of any adaptive, opto-mechanical system, projection and display system under virtual environmental conditions (heat, stress,...) that will affect the optical performance.

The diffraction theory of aberrations involves the calculation of the Rayleigh-Sommerfeld (RS) integral taking into account that the wave arriving to the diffracting aperture is affected by the aberrations of the optical system and assuming the exit pupil (EP) as the diffracting aperture. This last assumption is just an approximation, since the actual diffracting aperture is the aperture stop (AS) of the system. In this work we show that using the geometrical-numerical approach for the calculation of the RS integral developed at the Optics Laboratory of the Universitat de Barcelona, it is possible to perform the calculation of the point spread function (PSF) of an optical system using as diffracting aperture the AS or the EP. We will prove that the results may indeed be different in some cases and we will present experimental evidences.

Normally, depth of focus and resolution of an optical system are complementary parameters. According to an established technique known as wavefront coding the depth of focus can be enhanced by inserting a phaseplate with a cubic surface function into the exit pupil plane of an optical system. Although contrast is reduced the image quality can be restored very efficiently by inverse filtering because the modulation transfer function (MTF) almost does not change when the system is defocused. In addition the MTF has no zero crossings. Therefore inverse filtering has no singularities. Thus, three dimensional objects can be imaged with microscopes with a large depth of focus. The waveoptical performance of a commercial microscope equipped with a cubic phase plate has been simulated. The simulation results are discussed and compared with experimental data. The system has been analyzed both regarding effects specifically related to the phase plate design and regarding effects related to the optical properties which result from the combination of the phase plate with the microscope system. A variable phase plate design is also presented which can be adapted to specific objects and optical systems.

In this work, we present a new image-quality-based optimization process using a USAAF test to estimate the contrast function in the image plane. This strategy permits us to estimate the contrast values with only one image for the analyzed field, so the computation time of the method is appropriated for an optimization process. This image-quality-based procedure does not present the typical problems in estimating the contrast value in optical systems with odd wave-aberrations because the method uses an image of one extended object. The optimization process is applied to design triplet systems. For a triplet lens system working with an f-number of eight, we obtain a design with a Strehl ratio of 0.91 at full field of view using our optimization process. Finally, we present the optimization process’ dependence on the starting systems which is not in correlation with the starting systems’ quality.

A general method is presented for the exact numerical resolution of Maxwell’s equations for monochromatic wave propagation in a two-dimensional waveguiding structure. The Generalized Source Method using the Green tensor of free space leads to an exact solution of a wide variety of guiding as well as leaky mode structures without setting boundary conditions and without resorting to PMLs.

In this work, we present a new method for calculating the primary aberration tolerance for optical systems with absorption. This method is based on obtaining a loss function of the system at the exit pupil and using this function to modulate the transmittance amplitude of exit pupil. Finally, the aberration tolerance is obtained by applying the Steel’s modification of the Maréchal tolerance method using a loss function to modulate the transmittance amplitude of the exit pupil. This method permits us to calculate the primary aberration tolerance taking into account absorption factors other than the annular pupil. We applied this method to calculate the primary aberration tolerance of a cemented achromatic doublet taking into account the energy losses due to the change of medium.

The presence of ion impurities in a liquid crystal cell has a detrimental effect on the performance of the cell in terms of switching times and optical response. Here we present simulated and experimental results showing the effect of these impurities at different states of switching.

The concept of the simplest possible reflecting anastigmat is discussed and anastigmats consisting of four spherical mirrors are introduced in this context as being the last remaining family for which the solution set has not been thoroughly mapped. A method for mapping the solution space for four-spherical-mirror anastigmats is described and results are presented. Analysis of the large number of solutions obtained in this way is in its initial stages, and some of the early results are presented here.

All-reflective optics is conventionally required for extended spectral region observations in astronomical spectrograph. But the spatial resolution is usually not good enough while the large-size CCD will be used for observation in all-reflective optics. In this paper, all-refractive optics has been investigated to design a fast (F/1.55) and wide angle camera objective for large spectral coverage, from UV to VIS and up to NIR, when a large-size CCD is used on the focal plane of the spectrograph of Mont Megantique telescope. The case of achromatic and apochromatic condition has been investigated for axial and lateral color controls. The new proposed solutions have been optimized from two to three different glass combinations in order to have higher throughputs for large spectral coverage, especially in UV region. The used components have been minimized to reduce the light inherent lost. The monochromatic aberrations have been corrected and controlled by using optimized lens bending and shapes to make the camera have the CCD pixel resolution. Ray tracing results displayed the good optical performance of the camera to cover from 350 nm to 1000 nm spectral region with high resolution. The broadband AR coating, enhanced on UV region, will be used on each surface of the lenses in the camera. Final throughputs for the designed camera has been estimated and given in the paper.

The introduction of Image Slicers in Astronomy has been growing rapidly in the recent years. These optical devices allow the simultaneous observation on the same detector matrix of two-dimensional sky maps and the spectral decomposition of light on all of their angular samples, therefore dramatically reducing the observation times and getting rid of the spectro-photometric variations of the atmosphere. Today the implementation of Image Slicers is planned on various ground and space telescopes, covering a spectral domain ranging from blue to mid-IR wavelengths. Among such different projects, we describe the Image Slicer of MUSE (Multi Unit Spectroscopic Explorer), a second-generation Integral-Field Spectrograph for the VLT combining a 1’ x 1’ Field of View with a spatial resolution of 0.2” and a spectral resolution of 3000. The most efficient principle of an Image Slicer consists in a combination of several different optical channels, each made of three mini-mirrors having different tilts and curvatures. After a brief presentation of the MUSE Image Slicer requirements, we will explain the followed logic in order to optimize the opto-mechanical design and cost of the Slicer: indeed one of MUSE peculiarity is the total number of its individual modules, that is 24. The realization of such series at an affordable cost actually is a design driver of the study. The communication also deals with the used optical design models, the expected performance, the candidate technologies for the manufacturing of all the components, and the future development of a prototype of this critical optical subsystem.

SNIFS is an integral field spectrograph devoted to the observation of supernovae. This instrument is today in the manufacturing phase and should be able to observe supernovae at the end of this year (2003) on the 2.2m telescope of University Hawaii. The concept of SNIFS is to split the 6” x 6” field of view into 225 samples of 0.4” x 0.4” through a microlens array. Then the spectral decomposition of each sample is imaged on a 2k x 4k CCD. In order to cover all the large spectral range with a high resolution, the spectrograph is composed of two modules, one for the blue wavelengths (320 nm to 560nm)with a resolution around 1000 at 430 nm and one for the red wavelengths (520 nm to 1 µm) with a resolution around 1300 at 760 nm. First we will present the optical design and detail the function of each optical component. Then the mechanical design will be shown with some maps of the structure. Finally the first pictures taken during the alignments will be displayed.

Natural fluorescence is a very weak signal, which represents only a very small fraction of the light emanating from the surface. The only method to detect natural ground fluorescence is to observe in the Fraunhofer lines of the solar spectrum where the otherwise much stronger reflectance background is significantly reduced. Ideally, would a Fraunhofer line be completely dark, the fluorescence would introduce some light at the line position visible on a black background. The spectrometer is calculated for four Fraunhofer lines, any combination of which can be used for the measurements. The first concave pre - dispersing grating focuses the selected lines to the entrance slits. The second part of the device consists of two concave diffraction gratings, one for the blue channel, and one for the red channel. These gratings focus light to the same detector array. No other optical elements are necessary. Spectrometer shows diffraction limited image quality. All the gratings surfaces have spherical form. This spectrometer has small dimensions (about 350 x 250 x 70 mm) and can be attractive for the space applications. Several modifications of the spectrometer and some aspects of its diffraction gratings fabrication and their diffraction efficiency are discussed.

Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System, is a project to develop a system of four wide field synoptic telescopes. It is designed to accomplish many of the science goals envisioned by the decadal review for LSST. The primary mission of Pan-STARRS is the detection of potentially hazardous asteroids (PHA), secondary science objectives are a (nearly) all-sky survey, a medium-deep survey, an ultra-deep survey, and studies of variability. This paper discusses the basic design choice of a distributed system of four telescopes and the details of the optics design.

COROT is a mission of the CNES space agency, to be launched in 2005 in a Polar orbit. Its main goals are the search of stellar oscillation and the exoplanet detection. Five star fields chosen close to the galactic plane and in the opposite direction will be observed with an high photometric stability. Four 2048x2048 CCD detectors cover two detection areas one for asteroseismology and the other for exoplanets detection. To avoid the saturation risk the seismology area is just in front of focal plane; in the exoplanet area a low power prism disperses the images to get color information about each observed star. This paper presents the procedure used to deduce the polychromatic PSFs for both the seismology and the exoplanets detection areas depending on position and star color indexes. The use of standard optical packages, the expected inaccuracies and performances are discussed.

The MAGRITTE telescopes are part of the SHARPP instrument suite, part of the Solar Dynamics Observatory (SDO), a NASA spacecraft to be launched in a geostationnary orbit in 2007. The MAGRITTE instrument package will provide high resolution images of the solar corona at high temporal frequency simultaneously in 5 EUV and in Ly-α narrow bandpasses. The 1.4 R₀ MAGRITTE common field of view complements the other SHARPP instruments, as well as its spectral coverage with 6 narrow bandpasses located within the 19.5 to 120 nm interval. The key challenges of the MAGRITTE instrument are a high angular resolution (0.66 arcsec/pixel) with a high responsivity (exposure times smaller than 8 sec), combined with restricted spacecraft resources. The design of MAGRITTE is based on a high performance off-axis Ritchey-Chretien optical system combined with a large detector (4 K x 4 K, 12 µm pixel). The tight pointing stability performance of 1.2 arcsec over the image exposure time requires an active image motion control, using pointing information of a Guide Telescope, to compensate low frequency boresight variations produced by spacecraft jitter. The thermomechanical design and the mirror polishing are highly critical issues in the instrument design. This paper presents the MAGRITTE design concept with the expected performances based on a realistic error budget. The mirror polishing concept and performances are discussed.

Remote sensing of a range of pollutants in the lower Earth atmosphere requires high spectral resolution (0.1nm to 1nm) and high signal to noise ratios, in UV, visible and near-IR spectral bands. Sensing of large Earth areas from Geostationary orbit (GEO) has critical advantages in monitoring the origins and transport of pollution on hourly time scales. The sensor concept is a pushbroom imaging spectrometer using a common all-mirror telescope with a set of three grating spectrometers and area-array detectors. The challenges in optical design include requirements for excellent colour correction to achieve spatial registration over wide spectral bands, and operation at high relative aperture. These aims are achieved by use of novel spectrometer design concepts, including use of a convex diffraction grating in a concentric configuration. Calibration concepts, including a ratioing technique for absolute measurements, are briefly described.

EADS SODERN is developing a compact highly stable near infrared laser dedicated to a space cold atom clock (PHARAO program supported by the CNES). The laser is based on an extended cavity diode laser (ECDL). We will present the design, preliminary performances and the environment behaviour of this ECDL. The ECDL is spectrally tuned with an intra-cavity Fabry-Perot filter. It emits 30mW laser power at a wavelength of 852nm with a line-width around 100kHz. The laser frequency is servo-locked on a saturated absorption line of a cesium vapour. It provides a relative frequency accuracy of 3x10^-9 and a frequency noise spectral density lower than 10⁴Hz²/Hz in the range 100Hz to 1kHz. An acousto-optic modulator enables a fast and accurate tuning of the laser frequency, over a 80MHz range, with a rising time of 200GHz/s. According to the results of the mock-up, the flight model under development is expected to be the most accurate and stable laser for space. Beyond the intended application of space-based cold atom clock, such a stabilized laser could also be a key element for future on-board instruments such as space interferometers or space LIDAR, for which a highly stable optical frequency standard is required.

Natural and anthropogenic trace constituents play an important role for the ozone budget and climate as well as in other problems of the environment. Atmospheric trace aerosol distribution plays an important role in key evolutions of the Earth atmosphere, such as stratospheric ozone depletion and greenhouse effects. In order to monitor those changes and to try to prevent their dramatic impact, exchange processes between the stratosphere and troposphere as well as the distribution and deposition of tropospheric trace constituents are investigated. The mission and the design of the Limb Infrared Fourier Transform spectrometer (LIFT) instrument are described. This instrument supply observation of species with regard to eight specific questions centred on climate-chemistry interactions and the role of anthropogenic emissions. LIFT will globally provide calibrated spectra of the atmosphere as a function of the tangent altitude. The users will subsequently retrieve altitude profiles of the target species from the spectra. LIFT field of view will be 30 km in elevation and in azimuth. The resolution of this instrument is 30 km in azimuth corresponding to the full field of view, while it is only 2 km in elevation, obtained by using a matrix of 15x15 detectors. The instrument will cover the spectral domain 5.7-14.7 μm through 2 different bands respectively 13.0-9.5 μm, 9.5-5.7 μm. With a spectral resolution of 0.1 cm^-1, LIFT is a high class Fourier Transform Spectrometer compliant with the challenging constraints of limb viewing and spaceborne implementation.

Multiple-Aperture Optical Telescopes (MAOTs) are a promising solution for very high resolution imaging. In the Michelson configuration, the instrument is made of sub-telescopes distributed in the pupil and combined by a common telescope via folding periscopes. The phasing conditions of the sub-pupils lead to specific optical constraints in these subsystems. The amplitude of main contributors to the wavefront error (WFE) is given as a function of high level requirements (such as field or resolution) and free parameters, mainly the sub-telescope type, magnification and diameter. It is shown that for the periscopes, the field-to-resolution ratio is the main design driver and can lead to severe specifications. The effect of sub-telescopes aberrations on the global WFE can be minimized by reducing their diameter. An analytical tool for the MAOT design has been derived from this analysis, illustrated and validated in three different cases: LEO or GEO Earth observation and astronomy with extremely large telescopes. The last two cases show that a field larger than 10 000 resolution elements can be covered with a very simple MAOT based on Mersenne paraboloid-paraboloid sub-telescopes. Michelson MAOTs are thus a solution to be considered for high resolution wide-field imaging, from space or ground.

This paper describes a hybrid optical system using a combination of glass and polymer optics, including aspheric surfaces, in a Wide FOV Head Mounted Display (HMD) for Simulation and Visualisation.

This paper gives a review on the design and use of both amplitude filters and phase filters to achieve a large focal depth in incoherent imaging systems. Traditional optical system design enhances the resolution of incoherent imaging systems by optical-only manipulations or some type of post-processing of an image that has been already recorded. A brief introduction to recent techniques to increase the depth of field by use of hybrid optical/digital imaging system is reported and its performance is compared with a conventional optical system. This technique, commonly named wavefront coding, employs an aspherical pupil plane element to encode the incident wavefront in such a way that the image recorded by the detector can be accurately restored over a large range of defocus. As reported in earlier work, this approach alleviates the effects of defocus and its related aberrations whilst maintaining diffraction-limited resolution. We explore the control of third order aberrations (spherical aberration, coma, astigmatism, and Petzval field curvature) through wavefront coding. This method offers the potential to implement diffraction-limited imaging systems using simple and low-cost lenses. Although these performances are associated with reductions in signal-to-noise ratio of the displayed image, the jointly optimized optical/digital hybrid imaging system can meet some specific requirements that are impossible to achieve with a traditional approach.

Since the early years of zoom optics, Angenieux has been involved in cine 8 mm, 16 mm and 35 mm. Among more than twenty different zoom lenses, four of them have been milestones in this field, technical progresses being sanctified by two Oscars in 1964 and 1990. From 1960 to 2002 Angenieux has created first the 4 x 35 LA2, the first four times mechanically compensated zoom lens for cine 35 mm in the world, secondary the 10 x 25 T2, the first ten times mechanically compensated zoom lens for cine 35 mm in the world, then the 10 x 25 HR, the top level of quality for its category and finally the 12 x 24 Optimo with all characteristics and performances greatly increased. This leadership has been reached thanks to computers and in-house softwares but also thanks to new manufacturing processes.

Micro cameras for mobile phones require specific opto electronic designs using high-resolution micro technologies for compromising optical, electronical and mechanical requirements. The purpose of this conference is to present the optical critical parameters for imaging optics embedded into mobile phones. We will overview the optics critical parameters involved into micro optical cameras, as seen from user point of view, and their interdependence and relative influence onto optical performances of the product, as: -Focal length, field of view and array size. -Lens speed and depth of field: what is hidden behind lens speed, how to compromise small aperture, production tolerances, sensitivity, good resolution in corners and great depth of field -Relative illumination, this smooth fall off of intensity toward edge of array -Resolution; how to measure it, the interaction of pixel size, small dimensions -Sensitivity, insuring same sensitivity as human being under both twilight and midday sunny conditions. -Mischievous effects, as flare, glare, ghost effects and how to avoid them -How to match sensor spectrum and photopic eye curve: IR filter, and color balancing. We will compromise above parameters and see how to match with market needs and productivity insurance.

The basic design physics of a 3X riflescope is discussed. Overall, it is shown that a simple paraxial analysis provided the confidence of a practical solution. The objective and relay were designed together but separate from the eyepiece. The two systems were then put together with no further optimization. The scope was manufactured and awaits further tests for optical and overall system application performance by the user. So far, the optical performance appears to be as predicted. However, further analysis was done after manufacture which showed that a much better design could have been achieved without splitting the elements of the relay lens into an air-spaced doublet. Having a cemented doublet would have helped to achieve lesser sensitivity to manufacturing tolerances even though the nominal performance is slightly lower. This shows that a simple choice for an appropriate design constrain could result in a large impact on the overall manufacturability of an optical design.

We present the design of a lens for CCD or CMOS sensors using a new generation of lenses with electrically controlled focal length. These new elements made out of liquids (a drop of oil in water) work according to the principle of electro-wetting: the spreading of a drop of water on an electrically insulating surface can be modified by creating an accumulation of charges at the base of the drop. The densities of the two liquid phases are matched in order to keep the phases in place whatever the position of the lens. This new lens can be used in small devices to achieve auto-focus camera modules. There are several ways to integrate our adaptive optic in a fixed camera module lens, classically made up of plastic lenses. We will discuss three different configurations for a VGA system with 4 mm focal length, f/3 aperture, 60° field. The optical resolution is excellent, for object distance going from 50 mm to infinity.

The display of 3D images containing all the depth cues required by the human vision system can be achieved using a reconfigurable Computer Generated Hologram (CGH) with high pixel count. Giga-pixel scale displays or spatial light modulators are required in order to form directly viewable 3-D images of 0.5m in size. A new Spatial Light Modulator (SLM) solution, Active Tiling (AT)¹, has been developed by the authors to replay giga-pixel scale CGHs at video refresh rates. This has overcome a key bottleneck preventing commercial development of electro-holography to date. At the heart of an AT system is a set of replication optics which produces multiple images of an electrically addressed Spatial Light Modulator (SLM) on an optically addressed spatial light modulator (OASLM). Solutions employed within electronic holography will be discussed. A holographic 3D display system using a 4 channel Active Tiling modulator with a new replay optics system has demonstrated directly viewable 3-D images and animations from 100 Mega-pixel CGH data. This provided viewing of both horizontal parallax only (HPO) and full parallax 3-D images up to 140mm in size.

The original optical design for two steps recording of the holographic diffraction gratings is presented. It gives the combination of the merits of two previously developed methods in one. From one hand, due to recording in two steps, we can use wide possibilities of the aberrations compensation. From another hand, we can record both the gratings - objective and the final grating in spatially incoherent light. This simplifies the technology of the holographic recording. Previously per limit one of the two steps required using of the spatially coherent light. Method does not require using of the additional optics. Both surfaces of the grating - objective blank have spherical form. The blank of the final grating can be plane - concave, which is usual for diffraction gratings. Since the blaze angle of the grating, recorded in the counterpropagating beams is determined by the recording geometry, and the efficiency of the grating depends on the polarization of the incident light, the transmission calculations with taking into consideration the polarization also have been provided. The transmission of the system is optimal for the S polarized light, the addition increasing of the transmission can be achieved by using of the immersion grating - objective.

Two optical set-ups for electronic speckle pattern shearing interferometry (ESPSI) using photopolymer diffractive optical elements are presented. Holographic gratings are recorded using an acrylamide based photopolymer material. Since the polymerisation process occurs during recording, the holograms are produced without any development or processing. In both ESPSI systems the photopolymer gratings are used to shear the image. In the first ESPSI system only one grating is used in combination with a sheet of ground glass. The distance between the grating and the ground glass can be used to control the amount of the shear. The sheared images on the ground glass are further imaged onto a CCD camera. In the second ESPSI system two gratings are used to shear the image. The gratings are placed between the object and an imaging lens in front of the CCD camera. The distance between the two gratings controls the size of the shear. The ESPSI system with two photopolymer holographic gratings is compact and suitable for industrial applications. Introducing photopolymer holographic gratings in ESPSI gives the advantage of using high aperture optical elements at relatively low price. Both of these interferometric systems are simple and flexible.

Diffractive optical elements (DOE), also known as computer generated holograms (CGH), can transform an illuminating laser beam into a specified intensity distribution by diffraction rather than refraction or reflection. These are widely used in coherent light systems with beam shaping purposes, as an alignment tool or as a structured light generator. The diffractive surface is split into an array of sub-wavelength depth cells. Each of these locally transforms the beam by phase adaptation. Based on the work of the LSP lab from the University of Strasbourg, France, we have developed a unique industry-oriented tool. It allows the user first to optimize a DOE using the Gerchberg-Saxton algorithm. This part can manage sources from the simple plane wave to high order Gaussian modes or complex maps defined beams and objective patterns based on BMP images. A simulation part permits then to test the performance of the DOE with regard to system parameters, dealing with the beam, the DOE itself and the system organization. This will meet the needs of people concerned by tolerancing issues. Focusing on the industrial problem of beam shaping, we will present the whole DOE design sequence, starting from the generation of a DOE up to the study of the sensitivity of its performance according to the variation of several parameters of the system. For example, we will show the influence of the position of the beam on diffraction efficiency. This unique feature formerly neglected in industrial design process will lead the way to production quality improvement.

Nowadays, in computer-generated diffractive optical element design or correlation filter computation, cell-oriented techniques incepted in the 1960’s or early 1970’s are sometimes still being used. It can seem surprising since point-oriented techniques have proved to provide better performance than cell-oriented ones. In this paper, we show that unless extremely short computation times are required, cell-oriented techniques should be avoided and point-oriented techniques should be preferably used because they always provide significantly better performance for a given space-bandwidth product: we extend the approach we already used for the implementation of correlation filters onto spatial light modulators (SLMs) to the design of diffractive optical elements (DOEs) and their implementation onto SLMs. In any case, even if the design is much simpler and the physical meaning clearly appears when cell-oriented methods are used, the performance in terms of diffraction efficiency and signal to noise ratio remains poor. An objective comparison is given with the help of the optimal trade-off framework. Simulations as well as experimental results are provided for various cell-oriented and point-oriented methods. Optical implementations are carried out with a twisted nematic liquid crystal SLM.

Immediately following an optimization sequence, many designers typically implement sensitivity analysis prior to more intensive tolerance analysis and system error budgeting. This paper proposes a method of automating optical design optimization into a two stage process which incorporates design sensitivity into the optimization process. The first stage consists of the standard optimization approach where the error function is a user defined combination of system performance as well as optical and physical parameter constraints. The second stage amends the error function to include the minimization of incident ray angles on each optical surface as part of the error function. The amendment to the error function in the second stage targets the root mean square of incident angles of sample rays. These rays may typically consist of the marginal ray to the image center, as well as the upper and lower rim rays to the image corner. A priority is placed on reducing large angles as the result of a least squares method. This paper will address the detailed implementation of the proposed approach inside of the optical design program. Practical examples will be presented where the proposed optimization has reduced the system sensitivity to manufacturing errors without substantially effecting image quality. The results of incorporating the amended error function into an automated global optimization approach will be described.

We have shown recently that, when certain quite general conditions are satisfied, the set of local minima in the optical merit function space forms a network where they are all connected through optimization paths generated from saddle points having a Morse index of 1. A new global optimization method, that makes use of this linking network to systematically detect all minima, is presented. The central component of this new method, the algorithm for saddle point detection, is described in detail and we show that the initialization of this algorithm has a significant impact on the performance. For a simple global optimization search (Cooke triplet) several representation forms of the network of the corresponding set of local minima are presented. These representations, which can be visualized in two dimensions, are independent of the dimensionality of the design space so that they can provide insight into the topography of merit function landscapes of arbitrary dimensionality.

The shortcomings of the standard glass 'maps’ that currently appear in optical design programs are discussed. There is a clear benefit in having a glass map that is interactive, i.e. allows the user to change system glasses directly from the map. This has been implemented in the WinLens software, and the work is reviewed in this paper. Most aspects of this 'active’ map can be customized to suit the requirements for any given lens design task. Standard maps, such as n-v-diagrams, may be generated, but for non-standard wavebands. Unusual variable combinations, such as internal transmission versus dispersion, may also be displayed. Finally, glasses in these plots may be color coded to display one or more extra optical, chemical, mechanical or thermal properties. These simple new tools can reveal significant correlations between properties and allow the designer to effectively consider a wider range of properties in his glass selection.

A biocular magnifier is an optic that is sufficiently large to be used by both eyes together, and which presents a magnified virtual image at a finite distance from an observer. The design of such an optic is one of the most difficult tasks in optical design due to the extreme optical parameters, the relatively high level of residual aberrations, and the interface between the image and two-eye vision. As such, biocular magnifiers of reasonable magnifying power (>x4.5) cannot easily be analysed in a meaningful way using conventional optical design software. A number of years ago, a unique computer program was written that enabled the analysis of biocular magnifiers in the way in which they were used, that is with the spatial image being viewed by two small mobile apertures of nominally fixed separation. Utilising the power of modern PC computers, this program has been extended considerably so that it provides detailed graphical analysis of the visual aberrations appropriate to an extreme optical system usable by both eyes together. The reasoning behind the software and examples of the graphical analysis of biocular designs is given in the paper.

The importance of having a standard form for transferring optical data between Computer-Aided-Optical-Design (CAOD) programs and other, mechanical, electronic, architectural, etc. Computer-Aided-Design (CAD) programs is stressed. Emphasis is put on the need to hold all data required for the model of a large-scale project in a standard retrievable form; optical data forms a small but vital part of this. Working in liaison with ISO TC 184/SC4 (the group concerned with “Industrial Automation” and development of STEP, the Product Modelling standard, ISO 10303), ISO TC 172/SC1/WG4, (“Optics and Optical Systems/Fundamental Standards/Electronic Data Exchange”) has made the first steps towards integrating optical data with other product data. The aim is to present all data necessary for the automatic design of optical systems in a unique and unambiguous format so that it can be safely processed by any other design software that conforms to STEP regulations. Since STEP is planned to embrace all manufactured products it is a very complex standard and fitting the optical data into its format is a lengthy procedure. By international collaboration, the Application Protocol, which defines in STEP terms the optical information to be specified, and the recently completed Application Activity Model, a necessary preliminary stage in STEP mapping the manufacturing process, have been produced and are explained here. Current work on the next stage which involves creating an Application Interpreted Model or EXPRESS schema of the AAM is then described.

We show in this paper how the field of diffractive optics has moved during these past twenty years from academic research to main stream industry and consumer electronics. We analyze the main driving forces, the various enabling technologies and techniques for both design, fabrication and mass production of diffractive optics, and the successive markets in which this technology has been able to provide economically viable solutions to specific industrials needs. More specifically, we will see how niche applications making use of special features of diffractive optics seem to survive the applications involving the same diffractives, issued from the successive main technology driven investment bubbles.

Quantitative analysis of stray light in optical system is often a burden for optical designers. Ghost images due to multiple reflections on the surfaces of lenses and mirrors must be minimized during the design and optimization phases. Stray light in general must be controlled also during the optomechanical drawings. Already presented at the ICSO 2000 conference (Ref. 1), the CODE V macro software PARASIT makes it possible to have a complete quantitative analysis of the ghost in a few minutes. The possibilities of PARASIT are summarized with emphasis given to recent developments and comparison are given with LightTools. To make a full evaluation of the stray light in general, the possibilities of Light Tools, MATLAB and EXCEL interacting together using the Microsoft Active X protocol are unbeatable, as long as methods and corresponding macros written in EXCEL VBA and MATLAB .m are at the disposal of the optical designer. A short overview of these possibilities are demonstrated in this paper.

Ray-tracing codes used for stray light analysis or illumination system design often require access to complex object shapes. This is sometimes achieved by designing objects in CAD packages, and then importing them into the ray-tracing package. The disadvantage to using imported CAD objects is flexibility, ray-tracing speed, and in some cases, ray-tracing accuracy. This paper describes a new approach in which a user-defined object is used. The user-defined object is an external, user-supplied program called a Dynamic Link Library or DLL. The advantages to defining an object using a DLL, rather than the other methods listed above, are described and examples given which compare the two approaches.

A new concept for a flat digital image acquisition device for large field of views (FOV) has been developed. Antetypes for the optical system are compound eyes of small insects and the Gabor-Superlens. A paraxial 3x3 matrix formalism is used to describe the arrangement of three microlens arrays (MLA) with different pitches to find the first order parameters of the system. These considerations are extended to arrays of anamorphic lenses with variable parameters to achieve homogeneous optical performance over the whole FOV. The model is validated by implementation of different systems into commercial raytracing software. A trade-off between system length, sensitivity and diffraction limited resolution as well as aberrations is discussed.

Angénieux recently developed a low cost 100 mm F/1.25 lens for uncooled IR cameras. It is made of only 2 elements, thanks to the use of GASIR glass (Umicore product) and a diffractive surface. With regard to its equivalent in germanium, it offers similar performances, for a much lower cost due to the price of the optical material, molding, and no need for athermalisation. This lens can be used with new light-weighted night vision goggle ELVIR developed by Thales-Angénieux. We plan to also use GASIR in low cost zoom lenses for uncooled cameras. Starting with these examples, we will compare different available optical materials for IR, their characteristics, and respective advantages and drawbacks. We will deduct from it from rules of use for these materials, depending upon the envisaged use, spectral bandwidth and number of items manufactured.

A test bench has been developed at the ONERA in order to measure the spectral responses of infrared focal plane arrays. This test bench can deliver hyperspectral cartographies with rather good resolutions (better than 16 cm^-1) on large spectral ranges (from 1.3 μm to 20 μm). The principle of this test bench will be described and experimental results obtained with a 320x240 uncooled microbolometer array will be presented. As a conclusion, the ability of uncooled microbolometer arrays to make spectral measurements will be discussed.

An infrared spectroradiometer is being developed at the ONERA to make field measurements of radiance and emissivity of terrestrial surface materials (MISTERE). The instrument, entirely cooled, is a stationary Fourier spectrometer. The principle of measurement based on the sampling of a canted interferogram by a 2D array of detectors will be detailed and the expected performances in terms of resolution, free spectral range, signal-to-noise ratio and scan rate will be presented.

VISTA is a 4m class survey telescope designed to perform pre-planned, ground-based astronomy surveys of the Southern sky in the visible and infrared spectrum. The telescope includes a Cassegrain mounted infrared (IR) camera with a field of view of 1.65 degrees. The camera has no cold stop, and therefore the three lenses constituting the field corrector are positioned inside the cryostat of the camera. A window of 950mm diameter closes the cryostat. The lenses have a diameter of approximately 600 mm, and the third lens have its first surface with an aspheric profile. The large cryostat window and the aspheric surface of the third lens are the most difficult components to manufacture and test. To our knowledge, they are the largest Infrasil 302 components to be mounted and used inside a cryostat at 100K up to this date.

We present a novel technique for particle sizing, based on recent studies about near field speckles, that is simpler than the existing light scattering methods. We first recall the results about the so called near field scattering (NFS) condition for the light scattered by a disordered sample, discussing the main features of this remarkable region of the scattered light. Then we present the two standard configurations (homodyne and heterodyne NFS) adopted for carrying out NFS measurements. The two configurations are critically discussed and the great advantages of the heterodyne scheme are emphasized, such the extremely simple layout, the rigorous subtraction of stray light and the almost zero alignment requirements. Results obtained with suspensions of calibrated polystyrene spheres are presented and discussed.

A Fabry-Perot comprising a multilayer mirror and a mirror operating according to the resonant reflection of a grating slab waveguide exhibits the remarkable property of possibly being single order. The analysis of this new type of resonator is made and applied to the understanding of the operation of a known filtering laser mirror.

Chirped Bragg gratings are commonly utilized in optical fiber communication systems for chromatic dispersion compensation, because they realize a large dispersion and have very small dimensions and low insertion loss. Chirping can be obtained during the writing of the grating, for example, by bending the fiber so that a continuously changing period is projected on it or by applying a non-uniform strain on the fiber during irradiation, or by using a chirped phase mask. It is also possible to obtain and tune a chirped grating after the fabrication of grating by applying a temperature gradient or a strain gradient along the fiber. In this work we propose a simple technique for making tunable chirped gratings, which consists of the application of a uniform Bragg grating to the lateral side of a beam which was subsequently bent.

We propose an active and adaptative optics device dedicated to programmable femtosecond beam shaping, based on the use of an optically addressed light valve. A theoretical investigation of the system is presented. The experimental set-up incorporating an active beam shaping device, is depicted. Results are then described and discussed.

In the field of biophotonics the main goals are the control and processing of in vivo biological tissues and the monitoring of biomolecule dynamics. Two particular “pitfalls” are present: the dynamic multiscale organization and the photostress of the medium. Until now the state of the art of the pico-femtosecond systems designed to these applications shows that the changing laser technology has been only used as an add-on. Our approach is based on a bottom-up procedure and on the medium-centered knowledge. The range of neurobiological applications of ultrafast photonics extends from TRP (time-resolved propagation) to linear and non-linear TRE (time-resolved emission). The device combines a one kilohertz chirp pulse amplification laser system and a single shot streak camera. For discrete wavelength applications (TRE), the set-up is a SHG/OPG/OPA³/SHG design. In the case of TRP, the beam is focused into pure water to generate a white light continuum. After propagation through tissue, a single-shot streak camera with single photo-electron counting capability performs the picosecond time-resolved spectroscopy of the collected photons. Depending on the acceptable level of photostress, the integration time can extend from 33ms up to several minutes with a real-time control of the jitter and time drifts. The meaning of the TRE spectro-temporal image is particularly detailed in the 450-480nm excitation window in regards to the contributions of mitochondrial flavoproteins. This optical system fulfills the reliability and the sensitivity, conditions required for measuring opto-electronic quantities from freely moving animal at low irradiation.

We report on passive micro-resonator numerical simulations. These structures present a potential functionality in wavelength division access network. We study the influence of the gap between the micro-resonator and the coupling device. We show that greater than 75% optical power transfer to the drop port is enabled in polymer micro-ring by use of a dual-taper coupling method.

We have designed a cost-effective, fiber optic bundle-based detection system for microarray fluorescence measurements. A bundle, fabricated with thin-cladding fibers of 50-μm in core diameter, is used for spot excitation and collection. The collected optical signal is detected by a CMOS BDJ (Buried Double p-n Junction) detector, which can be operated either as a photodiode or as a wavelength-sensitive device. For improving measuring rate of a microarray, we have proposed a direct spot scanning technique, which is based on a prior knowledge about the predefined microarray's mask pattern, and operates to bring the bundle successively over each spot for single-point measurement. It is implemented with a microarray registration procedure to determine the spots' positions. The detection system with implemented scanning technique has been tested using microarray samples. Its scanning operation has been verified by comparing the determined spots' coordinates to the microarray image.

Reflection and transmission of the light in a random medium are composed by coherent and incoherent waves. The coherent one can be modeled as interacting with a medium with effective optical coefficients. In a random dilute suspension, the coherent wave travels in a medium with an effective index of refraction given by the van de Hulst formula. This effective index is, in general, complex. The imaginary part takes into account the loss of the coherent wave due to scattering. Internal reflection, due to random particles in suspension defines a critical angle determined by the effective index of refraction of the particles in suspension. The curve of reflectivity is smoothed near the critical angle by the imaginary part of the effective index of refraction. One can show that the diffuse component of the reflection tends to zero at the critical angle. In this work, laser reflectometry near the critical angle is used to study particle adsorption on a flat surface. We monitored the adsorption of polystyrene particles with positive and negative charge in suspension. This method allows the direct measuring of reflectivity and its angle derivative on the prism surface where is formed the film.

Optical Coherent Tomography (OCT) technique is based on an interferometric device bringing to the inter-correlation between a short reference pulse and the signal issued from the medium. This correlation is obtained by mechanical length modulation of the interferometer reference arm. We propose here an original technique using the SISAM (“Spectroscope Interferentiel a Selection par l’Amplitude de la Modulation”: Interferential Spectrometer by Selection of Amplitude Modulation) correlator, which allows to obtain directly without length modulation, the inter-correlation signal between the reference and the tests waves. With a large spectral bandwidth light source, the temporal depth of the original pulse is short compared to the signal diffused in the complex medium, and the inter-correlation function may be reduced to the impulse response of the structure to be studied. This temporal analysis could be very interesting to obtain both amplitude and phase parameters on the waves propagated in the medium, and could induce significant data on the medium and its structure. We will present the experimental SISAM device and results obtained in imaging through turbid media with this technique. We will also discuss about efficiency of this method in terms of accuracy and of ability to characterize complex structures and media.

A new miniaturized camera system that is capable of 3-dimensional imaging in real-time is presented. The compact imaging device is able to entirely capture its environment in all three spatial dimensions. It reliably and simultaneously delivers intensity data as well as range information on the objects and persons in the scene. The depth measurement is based on the time-of-flight (TOF) principle. A custom solid-state image sensor allows the parallel measurement of the phase, offset and amplitude of a radio frequency (RF) modulated light field that is emitted by the system and reflected back by the camera surroundings without requiring any mechanical scanning parts. In this paper, the theoretical background of the implemented TOF principle is presented, together with the technological requirements and detailed practical implementation issues of such a distance measuring system. Furthermore, the schematic overview of the complete 3D-camera system is provided. The experimental test results are presented and discussed. The present camera system can achieve sub-centimeter depth resolution for a wide range of operating conditions. A miniaturized version of such a 3D-solid-state camera, the SwissRanger 2, is presented as an example, illustrating the possibility of manufacturing compact, robust and cost effective ranging camera products for 3D imaging in real-time.

The coupling of a 2D focused beam under normal incidence into a grating waveguide was solved by means of a coupled wave formalism where the phenomenological parameters are given by a simple plane wave diffraction analysis [1]. It is shown that the guided modes which must be considered in the situation of normal incidence are waves exhibiting a standing wave as well as a propagating character. The plane wave diffraction analysis of the poles corresponding to these modes reveals their interesting properties and helps establish the suitable phenomenological representation of the coupling event. The aim of this approach was to find out the conditions for maximum light confinement in a grating waveguide in the perspective of the high efficiency excitation of a high density pixellated array of biosensor sites.

The application of near infrared multiphoton excitation to the laser-scanning microscope was first conceived by Denk, Strickler and Webb in 1990. Since then, advances in design have seen the multiphoton laser scanning microscope (MPLSM) applied to a wide range of biological research areas, including skin imaging and vaccine delivery. The technique has the attributes of low phototoxicity, high-resolution functional imaging to depths in scattered tissues. These characteristics have encouraged engineers and scientists to develop in-vivo imaging systems. For these applications, laser excitation pulses can be delivered to the sample through optical fibers. Although this solution provides a number of advantages relating to movement and flexibility of the site of interest relative to the laser source, the peak powers that can be delivered down the fiber are limited. We report on the design and commissioning of a directly coupled in-vivo MPM system, optimised for the imaging of epidermal vaccines delivered to a range of biological models and humans. Specifically, we seek to apply the system to visualise in-vivo, the influence of hand-held, helium powered needle-free systems on skin cells. A standard Nikon E600FN microscope, dissected above the optical plane was cantilevered from a vibration isolated table using rigid support arms. The modified microscope was coupled to an infrared optimised Bio-Rad Radiance 2100MP, multiphoton dedicated laser scanning control and image acquisition system. Femtosecond laser pulses were provided by a 10W Verdi pumped Mira Ti:Sapphire laser, from Coherent Inc. The microscope was modified such that the transmission half may be selectively attached for conventional imaging with ex-vivo and cell culture samples, or removed for in-vivo imaging of skin sites on the body of humans and large animals. Optical performance of the system, and aspects of its design and commissioning are discussed in this paper.

The I3O technology based on Titanium ion implantation in silica is proposed for the fabrication of passive compact PLC devices. It is demonstrated that the guided field can be easily tailored to fit standard fibers or can be compatible with the use of bent waveguides having a small radius of curvature.

Spatial solitons in liquid crystals can be observed with milliwatts of light power due to the nonlocal saturable nonlinear effect of field-induced director reorientation. In novel generations of all-optical switching circuits and optical networks spatial solitons show some promising possibilities. Director orientation in an LC-layer is simulated for a dc-voltage over the layer and an optical field injected lateral to the layer. Due to a torque induced by the electric field the molecules will tilt and the index of refraction in the layer will rise. The simulation of the soliton behavior is based on the Euler-Lagrange variational formula for the distortion free energy of the liquid crystal. The raise in the refractive index causes a self-focusing effect. When the self-focusing balances the diffraction, a spatial soliton can occur. A BPM-algorithm is used to simulate the light propagation in the layer. Without a dc-field, a large optical field for soliton propagation is required to reach the threshold to initiate the molecular reorientation of the liquid crystal molecules. A dc-field can be used to overcome the Fréederickz-transition so that a lower optical field is required. The relations between optical field profiles, dc-voltage and layer thickness which enable soliton propagation are discussed.

In this paper we report the experimental study of gain of telecommunication Erbium Doped Fiber Amplifier (EDFA). For particular pump power, the gain of Erbium Doped Fiber Amplifier for the wavelength range of 1529 nm - 1559 nm was measured and found that the gain of the Erbium Doped Fiber Amplifier is very uneven exhibiting peaks with different widths around 1532 nm and 1550 nm. On analysis of the results, filters of desired characteristic is suggested which could support for flattening the gain of EDFA for fixed pump power, so that the EDFA could be used for WDM applications. We have flattened the gain spectrum of a commercial Erbium-doped fiber amplifier, obtaining a curve with approximately ± 1.5dB of ripple, from 1530.1 nm to 1556 nm, using five fiber bragg gratings as equalizing optical filter.

The eyepiece design is one of the most challenging of all for the optical designer, since the result will be judged by the human eye, which is a very sensitive and subjective instrument. The combined effects of field curvature and astigmatism, geometric distortion, and the chromatic aberrations yield an optical system that is truly unique. No two eyepiece designs present an image that looks quite the same, and even different samples of the same design can produce different looking images due to the effects of manufacturing tolerances. In some cases the design must accommodate a large exit pupil to allow for head movement, and these dynamics introduce even more visual effects; image “swimming”, changes in distortion leading to “corner pulling”, and color fringing to name a few. When the design must be compact and weigh very little, the number of lens elements permitted is few and the design process becomes all the more difficult. The use of aspherics in the eyepiece design can compensate for the necessary limit on the number of lens elements. A case history in the design of a successful eyepiece is presented, showing the tradeoffs made in the selections of materials, aspheric complexity, fabrication concerns and packaging limitations. The performance capabilities of these designs will be discussed. The tools used to analyze optical image quality and the criteria upon which success was judged is also presented. The example used is a large exit pupil eyepiece designed to view either a miniature color CCD or LED display.

Essence of this paper is to expand the results published concerning the primary aberrations of a thin lens. Starting with the contributions of the two refracting spherical surface, we have added the effects of considering each one as a rotationally symmetric polynomial asphere. As previous studies, we have worked with the bending variable (B) and the conjugate variable (C). In addition, two different media surround the lens and it has not the aperture stop in contact in order to get the effect of the aspherical surfaces on off-axis aberrations. As a result, the Seidel aberrations are third order polynomials in the variables B and C, except for the field curvature and chromatic aberrations, which preserve their form as they are obtained for spherical surfaces. The expressions can be used to incorporate the increase use of these surfaces in the predesign of not only simple but complex optical systems too, even to model axial GRIN lenses as it has been proposed recently. Moreover, modern algebra systems can make use of them to get an initial design for further optimisation.

Commonly the creation of data structure in optical system design software with sequential ray tracing are realized on the basis of ordinary arrays. Homogenous data structures have restrictions, main of which is a problem of enhancement. Often new optical surfaces, elements and media cannot be embedded into old data structures. In this paper a new object-oriented model of an arbitrary optical system is presented. This model utilizes a new data structure based on graphs and LDS (linked data structures). The inheritance and polymorphism make the data structure adaptable and extendible. Also this approach offers modeling multi-configuration and zoom optical system by a native way.

In the case of imaging optics for imaging cellular phones, special attention has to be paid on the cost of the lens system. The number of lens elements has to be minimized, but the image quality has to be maximized. It is important that optimum quality/cost - ratio is found. The image sensor characteristics and human visual system preferences have to be taken into consideration as well for the design. In this paper, we present our new image quality metric. The performance of the metric is investigated using subjective tests on different lens designs and compared with MTF metric. We show that our metric has a good correlation with human observer and performs better than MTF metric. Finally, we give some examples of optimization based on our metric.

The subject of birefringence induced by spatial dispersion (BISD), also called intrinsic birefringence, recently became an important issue for 157-nm lithography. For the deep UV range, because of intrinsic absorption, only crystalline materials can be used as optical materials for lens manufacturing. The physical properties of crystals are basically affected by spatial dispersion, especially at very short wavelengths. The resulting BISD leads to a serious deterioration of optical image quality. Recently the mathematical formalism for analyzing those aspects of the BISD effect that are relevant for optical design has been published. In this work we give an equivalent but simplified derivation of these results. This mathematical formalism is then applied to optical system design and the correction methodology is discussed. An example of optical system is given that has been corrected for the BISD effect.

We present a new, one-dimensional, transfer matrix formalism for describing the spectral properties of a quasi-periodic integrated waveguide filter (reflection R, transmission T, overall losses L = 1 - R - T), where losses (essentially due to the modal mismatch between adjacent sections) are modeled as localized, Dirac-like singularities of the (complex) dielectric permittivity. As far as losses appear periodic, the coupling constant between propagating and contra-propagating waves is complex: such a distribution leads to a specific spectral response for L, different from that provided by homogeneous absorption. Besides, the transfer matrix of a unit cell (made of two quarter-wave sections of high and low indices) can be expressed rigorously in the frame of usual coupled-wave equations, even for arbitrary high index contrast. As a result, any periodic section can be represented by one transfer matrix only, whatever the number of unit cells. This can dramatically reduce the computational time by comparison with more accurate simulation tools such as Film Mode Matching (FMM) method.

We present here a design of a coupling element aimed to be integrated into a nanomechanical biosensor for functional genomic analysis. The operation principle is based on a sub-nanometer resolution optical measurement of a cantilever deflection caused by a surface stress when the target nucleic acid sample hybridizes to the nucleic acid probe on the active side of the cantilever. The resulting deflection, of the order of nanometers, is measured by an optical system, in which a laser beam reflects off the back of the cantilever to a position sensitive photo-detector. We study in this paper three polymer optical coupling systems which could allow to detect the presence of target nucleic acid on the cantilever by amplifying the deflection caused by the stress.

Alumina thin films were elaborated by the sol-gel method, using aluminium butoxide as precursor and acetylacetone as chelating agent to stabilize the sol. The dip-coating parameters (sol concentration and withdrawal speed) were optimized in order to get waveguiding films. For a 15 successive layers deposition and a 700°C annealing treatment, waveguiding films of about 900nm thickness were obtained, which have a 1.582 refractive index at 543.5nm. The influence of the annealing temperature was studied in the 100°C to 1100°C range, in order to follow the elimination of the organic compounds and the existence of stresses. IR spectroscopy shows that an annealing temperature of 800°C is necessary for the complete elimination of the OH and C=O groups of the residual organic compounds, which are derived from the chelating agent. In a parallel way, the Al to O atomic ratio tends to the theoretical Al₂O₃ composition, according to Rutherford Backscattering Spectroscopy results. The stresses in the film were measured by an optical method. Their evolution with annealing temperature is characterized by two regimes, depending on the organic compounds elimination and the crystallization process.

In this paper we describe the optical design of a catadioptric endoscope for the Joint European Torus (JET). The JET is the flagship experiment in the European nuclear fusion research programme. It is a large tokamak (Russian acronym for “toroidal magnetic chamber”) system located at Culham (UK). At the centre of this machine there is a toroidal (ring - shaped) vacuum vessel where the plasma is confined by magnetic fields. The endoscope explores in two wave bands (4.2 μm - 4.4 μm and 0.6 μm - 0.7 μm) an entire cross section of the vacuum vessel. It then creates for each wave band an image onto a separate area image sensor, located 5500 mm away from the plasma behind a concrete shield. The endoscope performs two different functions namely: infrared thermography on plasma facing components and in vessel inspection.

We shown the designs of optical collimators for wave length of 1.5 µm. The design is based in the Galilean Telescope formed with two kinds of lenses a convergent and a divergent. This design is a silicon negative microlens of 300 µm and of diameter and the positive lenses are discussing between several different materials of 6 mm of diameter, it is to determinate the best performance of the optical setup type Galilean telescope, the parameters of aberration and deviation rms. y p-v, we help to obtain the best system comparing the quantitative results that in this case was LaF3.

The complete analytical solution of the diffraction problem of an arbitrary incident wave by a 2D grating of arbitrary k-vectors is provided under the Rayleigh hypothesis. It is furthermore shown by deriving an analytical solution from the exact Generalized Source Method (GSM) in the limit of small grating amplitude that the Rayleigh and the exact methods lead to the same analytical results. This proves that the results given by the Rayleigh method in the limit of shallow grooves are exact whatever the groove profile.

A novel software tool has been developed to improve and optimize the design of optical multipass cells in long-path absorption spectroscopy. One of the main application fields of these cells is the monitoring of hazardous gases, where they become the transducers of a global fiber optic sensor. New techniques, based on solids modeling, have been applied for the description of the mirrors that constitute the multipass cell. These mirrors have been represented in terms of parametric surfaces known as NURBS (Non-Uniform Rational B-Spline). Under this approach, the design can reach a high degree of flexibility and versatility. The behavior of the multipass cell has been evaluated by means of different specific ray-tracing techniques that have been implemented taking into account the parametric nature of NURBS surfaces.

Performances of high quality imaging systems are often affected by surface or glass defects, like scratches, bubbles or other localized disturbances. The goal of the present investigation is the modeling of air inclusions in the lens material and analyzing the resulting changes in the wavefront distortion and in the diffraction spot quality. CD and DVD focusing objectives are especially sensitive to this type of defect, since the size of the diffraction spot and the power-density distribution determines the quality of both the written pits and received signal. We used OSLO and ZEMAX optical design software to model these errors. This model includes the DVD objective lens and the disc. The objective lens is a plano-convex lens made of glass with an aspheric layer on its convex side. Bubbles are incorporated as ball-shaped air inclusions. The computations are based on ray tracing and physical optics propagation methods. From these computations we can calculate the intensity distribution in the focal spot and the encircled energy in the Airy disk. These calculations help us determine the tolerances of DVD objective lenses to air inclusions in function of the bubble size, shape and position. The practical application of the model will allow us to redefine the quality criteria for the used DVD lenses.

Brewster angle technique has been recently well developed for the transparent anisotropy materials. In this paper, the Brewster angle for an absorbing biaxial medium is characterized using a cubic equation. It has been shown that there are infinite possible orientations for which the Brewster angles can be measured in absorbing crystals. The numerically simulated results were compared with available experimental data of the semiconductor CdSe. This theoretical investigation leads to the numerical solution of the refractive index parameters using the Brewster angle technique in uniaxial crystals.

Tolerancing aspheres and preparing the corresponding drawing indications significantly differ from techniques used at spherical lenses due mainly to surface waviness, an error caused by most asphere fabrication technologies. Standard (ISO) regulations proved to be adequate for several kinds of aspheric lenses (e.g. laser focusing/collimation) made by the traditional diamond turning method, but sometimes are not general enough for recent fabrication techniques (such as CNC polishing of glass aspheres), and today’s more demanding lenses (eyepieces, Fourier objectives, relays etc.). A new, generalized tolerancing technique has been developed to accurately constrain surface waviness, quite independently of fabrication technology, and to provide easy verification of the results. Operation of the method is demonstrated on a Fourier-type objective comprising a glass aspheric lens, by computer simulation and testing of the fabricated prototypes.

A systematic design method for quasi-symmetrical wide angle systems is presented. The method starts with thin lens predesign of half of the system using most available glasses. The aperture stop position is determined for reducing astigmatism and the system is made symetrical about it for eliminating Coma, Lateral colour and Distortion. Finally the system is optimized using Eikonal software for infinite conjugate.

Liquid Crystal Displays require controlled alignment of the liquid crystal molecular director at its confining surfaces. These surfaces may be coated glass or in the case of 'Liquid Crystal On Silicon’ (LCOS) technology, a silicon backplane. In the case of Vertically Aligned Nematic (VAN) cells an initially vertical orientation is used and from this the director may tilt in any direction. Some means is required to bias the tilt in a consistent direction to avoid the occurrence of differently oriented domains. For VAN cells one tilt bias method is oblique deposition of silicon oxide. An alternative method which eliminates concerns over consistency of deposition angle over a large substrate area is the use of surface relief structures to induce tilt bias. This is attractive for LCOS devices. Liquid crystal modeling tools have been used to simulate the effects of rectangular and triangular shaped 'bumps’ and 'dips’ protruding from and extending into the LC’s enclosing surfaces respectively. The director orientation and optical transmission of the LC pixels biased in this way are examined as a function of time during the switching cycle and spatially across the pixel to show that the combination provides controllable tilt bias.

The different methods of optical systems' optimization such as Newton and Least Squares along with their modification are discussed. Monte-Carlo technique as an statistical method which can overcome the shortcoming of those classic methods (such as the rate of convergence, the possibility of finding the overall minimum and avoiding local minima) is presented and compared with the other ones. An numerical example is presented to verify the method.

The Solar Disk Sextant (SDS) is an instrument conceived to monitor the diameter of the Sun and its oscillations. A key component of the SDS is the Beam Splitting Wedge (BSW), whose function is to provide calibration to the geometry of the focal plane. The thermal behavior of the BSW is critical, as it affects the overall performance of the instrument. Modeling the elements of the BSW and the basic thermal processes is shown to account for experimental evidences of defocusing observed in early measurements with a balloon borne prototype. Basic requirements for accurate thermal stabilization on board of the final instrument are derived.

An expert system for zoom lens design is developed. The Gaussian parameters of the zoom system are optimized using the damped-least-squares method to achieve smooth zoom cam curves, with the F-number of each lens group in the zoom system constrained to a rational value. Then each lens group is selected automatically from a database according to its range of F-number, field of view and magnification ratio as it is used in the zoom system. Design examples are given, which show that the scheme is a practical way for the automatic determination of initial layout for zoom lens design.

This paper describes the preliminary design of the so-called Transmit/Receive Optics (TRO) for the ADALIN lidar instrument on the future ADM Aeolus weather satellite. The TRO is the central optical unit of the instrument, that feeds the optical signals from the laser source to the emitting/receiving telescope, and vice versa, the received back scattered signals from the telescope to the spectrometers for Doppler shift evaluation. Additionally, the TRO supports a calibration branch, that bypasses the telescope (from the laser to the spectrometers) and aims at levelling out the received signals in terms of wavelength and signal height changes due to wavelength and intensity variations of the laser. Since the spectral range of the ALADIN instrument is narrow (centred at 354.8 nm), the TRO makes use of refractive optics (lenses) to a high extend. A 1 nm narrow band interference filter has been implemented on the reception branch on the TRO to suppress disturbing background signals. Special features of the TRO are two so-called aberration generators on the emitting and calibration branch, with which an artificial astigmatism can be realised for eye safety reasons. An opto-mechanical concept has been realised with four afocal optical groups, which are connected by parallel beams. Different design options for the aberration generator are being discussed with clear preference of a pure lens solution. The performance of the optical subsystem is monitored by extensive simulations, which are shortly summarised. As a specific simulation example, the analysis and trade-offs of the aberration generator are given.

I am very pleased to be able to share with the reader a summary of Rudolf Kingslake’s life and his contributions to the discipline of optical science and engineering, a discipline he really believed in with dedication and passion. Hilda Kingslake shared in a major part of Rudolf’s life (they were married for over 73 years and had been students of optics together for six years before their marriage). Hilda contributed a great deal of her own professional life to optics. They were both my friends and colleagues for thirty five years.