In this paper optical properties of silk fibroin (SF) thin films obtained via spin coating method are investigated. Work concentrates on the experimental examination of influence of relative humidity (RH) in the range of 7-90% in air on the changes of SF refractive index, thickness and optical path at room temperature. Spectral ellipsometry and interference methods are used for the SF thin films optical properties measurements. The sensing structure response value, response time and recovery time are presented. The results shows that RH significantly influenced the SF thin films thickness and refractive index what should be taken into account during the designing of optical devices based on SF. It also shows that SF thin films are promising material for room temperature RH sensors.
This work presents an investigation on the influence of different factors on conductive graft comb copolymer polymethylsiloxane (PMS) with poly(3-hexyltiophene) (P3HT) and poly(ethylene) glycol (PEG) or dodec-1-en as functional side groups grafted on poly(methylhydrosiloxane) backbone. The analysed factors that influenced the parameters of the layers were temperature and different gas atmosphere (N2, NO2). Samples were measured by spectroscopic ellipsometry under the influence of a gas atmosphere. Moreover, morphology (sample roughness) and optical properties (refractive index, extinction coefficient) were measured of obtained thin films deposited on glass substrate using spin coating method. The study showed that obtained thin films of copolymers shows the possibility of using such polymers in the implementation of gas sensing structures.
The paper presents the effects of the work aiming to build a device for spatial visualization of hypodermic blood vessels. The device was built using illuminators radiating polarized light of wavelength λ = 850 nm and two cameras in a stereoscopic set up equipped with polarizers and interference transmission filters, matched to illuminators. Images captured by cameras were analyzed by software that increases the contrast of blood vessels and extracts information about the distance from the hypodermic blood vessels to cameras. In this way the extracted course of blood vessels is recorded in the widely used in medicine DICOM format.
In the paper the planar waveguide based on SU-8 polymer were made on 2μm of silica (SiO2) on silicon (Si) substrates in order to obtain base for broadband interferometer. Analysis and calculation of sensitivity for single mode broadband differential interferometer were performed. Paper presents preliminary tests and analysis of such structures. Dilution of SU-8 solution for obtaining thin layer (below 500 nm) followed by elipsometric measurements is presented.
In the paper the planar waveguide based on SU-8 polymer were made on different substrates. As polymer layer Gerseltec SU8 GM1040 and Microchem SU8 2000.5 were used. By using Gerseltec SU8 GM1040 we obtained layer with thickness 950 nm which gave us planar waveguide bimodal structure for λ=633nm. By using Microchem SU8 2000.5 we obtained layer thickness 450 nm which gave us single mode waveguide structure for λ=633nm. As substrate we used 2μm of SiO2 on Si and standard microscope glass (soda-lime glass). Additionally the authors performed measurements for characterization of optical and physical properties of obtained layers. We measured layer thickness by Atomic Force Microscope (AFM) and by ellipsometer. Ellipsometry measurement also gave us refractive indices of waveguide layer and substrate. We also performed measurement of effective refractive index and attenuation of waveguide layers. Additionally we performed SEM measurement for checking layers adhesion.
An optical sensor of ammonia gas, based on the surface plasmon resonance (SPR) method has been investigated. The surface plasmon resonance (SPR) is very sensitive, and so is the optical technique used in chemical sensing. The angle of incident of light at which a resonant effect is observed, as well as the dip of a resonant are very sensitive to variations of the optical parameters of the medium on a surface-active plasmon metal layer. The sensing structures were made as follows. Gold layers were coated by means of vacuum evaporation on a substrate, 1 mm thick, made of a BK7 glass slide. The thickness of Au was about 48 nm. An active sensor layer of WO3 was deposited by thermal evaporation on the gold film while a Nafion"R" film was coated by means of the spin-coating method. The sensing structures were coupled on immersion oil with a prism coupler. A change of the intensity of light of the plasmon dip was observed when chemical active films (WO3 or Nafion"R") were exposed to varying concentrations of NH3. Optical ammonia gas sensors display a very fast response time and a fast regeneration time at room temperature.
The paper presents an optical-fiber hydrogen sensor. The sensor utilises a layered Fabry-Perot interferometer and includes gasochromic metal oxides (V2O5, Nb2O5, CeO2). The structure contains at the end a multi-mode optical fiber as the sensing element. The sensor permits to detect and to measure the concentration of hydrogen in a gaseous medium.
A comparison of the properties of selected gasochromic metal oxides in the interferometric sensor structures has been presented.
The paper deals with investigations concerning the optical parameters of the layers of selected phthalocyanines by means of the surface plasmon resonance method. The values of the refracting index and the coefficient of extinction for copper and lead phthalocyanines have been determined. The presented results concern the layers occurring in the surrounding atmospheric air before and after exposure to 100 ppm nitrogen dioxide. The obtained dispersive characteristics were determined ellipsometrically and using the surface plasmon resonance method, by adapting theoretical relations to the experimental dependence of the surface plasmon resonance. The resulting values of the complex refracting index for the tested phthalocyanines were compared with the values obtained by ellipsometric measurements.
The surface plasmon resonance spectroscopy is an optical technique that is capable of monitoring chemical and physical processes. It is sensitive to detect small changes of dielectric properties in a metal-phthalocyanine boundary. For this reason plasmon resonance phenomena have been used to characterize a number of different types of films. This work analyses the possibility of using the surface plasmon resonance phenomena in the detection of gas. Thin films of copper and lead phthalocyanines have been examined in the plasmon system from the point of view of their application in NO2 sensors.
The paper presents a way of determining the fundamental parameters of the design of a hydrogen sensor, the operation of which is based on the phenomenon of the resonance of surface plasmons (SPR - Surface Plasmon Resonance) in Kretschmann-Raether's system. The designed system has been realized. Its investigation results have also been presented.
The paper presents a layered sensing structure that permits to detect and to measure the concentration of hydrogen in a gaseous medium. This metal-dielectric-metal structure is a layered Fabry-Perot interferometer. The resonant cavity is made of WO3. The choice of just this material was dictated by its chemochromatic properties, i.e. the change of the optical properties due to the absorption of atomic hydrogen. In result of the absorption of H+ and e- the purely dielectric layer becomes a lost layer, displaying attenuation. The catalysis of molecular hydrogen to atomic hydrogen occurs in the palladium layer, which is also one of the mirrors of the interferometer. The measurement of the hydrogen concentration consists in the scanning of the angular variation of the interference peak position due to the absorption of hydrogen. The change of the peak position results from the change of the optical parameters of the Pd and WO3 layers.
The paper presents the results and way of measuring the dispersion of the complex refractive index of thin palladium layers in an atmosphere containing hydrogen with a concentration below the threshold of explosion (<4%). The measurements were carried out making use of exciting the surface plasmon wave.
The paper presents the structure of two laboratory models of waveguide planar sensors of refractive index changes of liquids. Both systems have been designed basing on plasmon resonance along the interface between metallic layer and measured liquid. The models have been constructed basing on planar waveguides as well as on strip waveguides. The measurement results of spectral transmittance of the investigated structures have been presented as the function of refractive index ofthe measured liquid.
The paper presents the structure of measuring stands to be applied to carry out spectral measurements of sensor layers sensitive to the presence of ammonia vapors in the atmosphere around. Also the structure of a model of the waveguide sensor for the detection of ammonia vapors has been presented, as well as the measurement results involving such a sensor.
The work presents the possibility to control the changes involving the difference of the propagation of waveguide modes TE0, TM0, TM1 by respective selection of technological parameters while producing the optics channel of the planar interferometer by ion-exchange technique in glass. The influence of the refractive profile of waveguide structure on the sensitivity of interferometer was observed.
The work presents the attenuation measurements of planar waveguides produced in the processes of ion exchange Ag+--Na+ and K+--Na+ in the selected types of glass. Also, the influence of waveguide heating on the extent of attenuation has been presented.
The work presents the structure of a computer-controlled set-up for the measurement of refractive index distribution using the measurement of synchronous angles and the IWKB method. Also, the measurement method of planar waveguide attenuation has been presented. In this method, light decoupling from the waveguide is carried out by means of immersion liquid. It ensures stability of coupling with the waveguide being measured, and furthermore, it enables full automation of the measurement process, as well as its application in the elaboration of measurement results.
The work presents the results of research work on some types of glass in view of their application as material for the production of waveguide structures using the technique of ion exchange Na+--Ag+ and Na+-- K+. In the testing, maximum changes of the refractive index of the glass (Delta) n, caused by the introduction of admixtures in the diffusion and electrodiffusion processes, were determined, as well as diffusion constants and mobility ratios of the exchanged ions.
The paper presents the results of research on the influence of long-term heating of planar waveguides at a low temperature (427 K), produced as result of ion-exchange K+--Na+ and Ag+--Na+ in chosen types of glasses, on their properties. The changes in the maximum value of a refractive index on the waveguide surfaces as well as diffusion constants for tested types of glasses at heating temperature were defined.
The present paper discusses theoretical and experimental research on the planar difference interferometer produced with the use of planar technique on a glass substrate plate (planar interferometers) in view of its application in the system of phase-polarization sensors of basic physical quantities.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.