We have designed and fabricated digital thermo-optic switches using low-loss photocuring fluoroacrylate polymers [1]. We have used both modeling and experimental design-rule studies to elucidate the contributions to loss and crosstalk of the various important building blocks that comprise a Y-branch digital optical switch (YDOS). We present herein the results of these studies as well as the achieved performance for 1x2, 2x2 and 4x4 switches fabricated with these designs. Average chip-level insertion loss values for the three designs were 1.1, 1.8, and 2.8 dB, respectively, for 1550-nm illumination. Switching times in every case were below 3 ms. Polarization dependent loss was less than 0.1 dB at 1550 nm. Fully packaged permanently pigtailed versions of the 2x2 and 4x4 switches were also constructed. For these packaged devices, average insertion losses of 2.0 and 3.3 dB were achieved, and crosstalk was maintained at a value less than -45 dB.

The demand in optical networking for photonic components that meet performance criteria as well as economic requirements has opened the door for novel technologies capable of high-yield low-cost manufacturing while delivering high performance and enabling unique functions. The most promising new technologies are based on integrated optics. Integration permits the parallel production of complex multi-function photonic circuits on a planar substrate. Polymeric materials are particularly attractive in integrated optics because of their ability to be processed rapidly, cost-effectively, and with high yields; because they enable power-efficient dynamic componentry through thermo-optic and electro-optic actuation; and because they allow to form compact optical circuits by offering large refractive index contrasts (index difference values between waveguide core and cladding). We compare the properties of optical polymers with those of other material systems utilized in integrated optics. We present an up-to-date snapshot of the global effort in optical polymer material development. We describe the criteria that optical polymers need to meet in order to be viable for commercial deployment. We review the state of the art in polymeric integrated optical components including switches, attenuators, filters, polarization controllers, modulators, lasers, amplifiers, and detectors. We further emphasize the practicality aspect by conveying which technologies have been productized successfully, which ones are ready for commercial introduction, and which ones are still under development in research laboratories.

We demonstrate a polymer waveguide-based thermo-optic variable optical attenuator array with 30dB dynamic range that requires less than 20mW of drive power to achieve 30dB of attenuation. The design offers low insertion loss and low polarization dependent loss. We also present simulation results that show good agreement with measured data and which thus permit to optimize the device performance.

We present results on the photorefractive performance of two different classes of organic materials. One of them is based on the space-charge field induced reorientation of the optical axis of chiral smectic A phases. In this case the orientational effect is linear in the field and it is due to the so-called electroclinic effect, in contrast with the quadratic effect present in nematics and associated with dielectric anisotropy. Besides presenting data on the photorefractive properties of these new mesophases, we will consider a simple model which describes their performance as a function of several material and geometrical parameters. In the second part of the paper we introduce cyclopalladated complexes as a new class of multifunctional photorefractive materials. Such molecules form amorphous phases which are photoconducting and exhibit a field dependent refractive index. Their efficiency is among the best known to date for organic materials and the simple synthetic route makes us foresee a fast optimization of cyclometallated compounds for photorefractive applications.

Polymeric photorefractive materials have attracted much attention over the past decade due to their potential applications, especially for optical information processing. However, their practical use has until now been limited, the available photosensitizers being efficient only in the visible range. Here, the chemical development and optical investigations of a photorefractive polymeric material active at 1500 nm are described. To our knowledge, this is the first such material to be reported. A conjugated poly[(ethynediyl)(arylene)(ethynediyl)silylene] acts as both an optical chromophore, as well as charge generator and conductor. Its absorption band tails into the near-IR hence providing charge generation at the 1500 nm excitation. The photoconductivity of the composite samples was measured with a dc-method using a 1500 nm diode laser source. The electro-optical coefficient was measured with a simple reflection technique. The photorefractive response was investigated with a two-beam coupling technique. The gain of the probe beam intensity, delivered from the pumping beam, reached 40 cm^-1 at the electric field strength of 650 kVcm^-1 thus confirming the photorefractive nature of the grating. The gain exceeded the absorption (30 cm^-1) that showed a good potential of this material for applications.

We report a new photochromic composite polymer that was evaluated in conjunction with its potential applications for optical holographic recording in the whole visible spectral range. It consists of poly-N-epoxypropylcarbazole (PEPC) polymeric matrix with a nitro-brome-substituted spiropyran (BNSP) photochromic dye. The PEPC+BNSP films can be considered as negative photochromic recording media. They are colored in the initial state and bleached upon irradiation within the whole visible spectra. When we placed the bleached samples to the darkness, they slowly revert to the colored form. The real-time holographic recording procedure in PEPC+BNSP films was studied.

Cholesteric liquid crystals, because of their birefringence and periodic structure, and 1-d photonic band-gap materials. In the reflection band, classical light propagation is forbidden for one of the two eigenmodes; for this mode, the material acts as a distributed cavity host. This inherent distributed cavity effect modifies the fluorescence spectrum, and, if the material is optically pumped, allows population inversion and mirrorless lasing. We have studied emission from thin samples of liquid crystalline materials optically pumped by pico- and nanosecond laser pulses. We have observed laser emission, without an external cavity, from dye-doped liquid crystals, from pure cholesteric liquid crystals without dyes, and from cholesteric liquid crystal elastomers. We present the results of these experiments, discuss the relation between material properties and the lasing process, and consider promising materials and applications.

Absorption spectra of lanthanideions in perfluorinated (PF) plastic solution were measured, and the radiative properties were determined by the absorption measurements and the Judd- Ofelt theory. Fluorescence spectrum of Nd³⁺ in PF plastic solution from 900 nm to 1350 nm, pumped at 580 nm, were measured for the first time. Lasing properties of a rhodamine 6G-doped graded-index plastic optical fiber laser (GI-POFL) and a rod laser were investigated. All measurements demonstrated the superior performance of the GI-POFL. This paper also discusses the lasing properties on the basis of near-field pattern measurements.

Charge injection in light-emitting diode (LED) structures is commonly achieved using metallic contacts, but the losses associated with metals at optical wavelengths are perceived to be one obstacle to the development of an electrically pumped polymer laser. We show that these losses might not be insurmountable by demonstrating the operation of a distributed-feedback polymer laser fabricated upon a corrugated silver substrate, using the material poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEH-PPV) as the gain medium. The lasing threshold of this device was increased by a factor of ~150 with respect to that measured for a similar device fabricated without the metal under comparable pumping conditions. The emission characteristics of the device were found to correlate well with the measured photonic band structure, enabling us to explain the effect of the microstructure on device operation.

In this paper we calculate the power lost to the SP on either side of a thin silver film bordered by Alq₃ and air. The possible recovery of power lost to the SP modes by means of wavelength scale nanaostructure is investigated. The role of a periodic scale nanostructure in the recovery of this power is then considered by examining the transmission and PL properties of both planar and periodically corrugated structures. It is shown that using the sample geometries choose that only one of the SP modes, the Alq₃/Ag SP, may be used to mediate PL emission.

A series of soluble arylamine-based hole transporting polymers with glass transition temperatures in the range of 97-108 degree(s)C have been synthesized. The synthetic methodology allows substitution of the aryl groups on the amine with electron-withdrawing and electron-donating moieties, which permits tuning of the redox potential of the polymer. The TPD-based monomers have been copolymerized with cinnamate-based moieties to obtain photo-crosslinkable polymers. These polymers have been used as hole-transport layers (HTLs) in multi-layer light-emitting diodes ITO/HTL/AlQ₃/Mg:Ag [ITO=indium tin oxide, AlQ₃=tris(8-hydroxyquinolinato)aluminum]. The maximum external quantum efficiency of the device increases as the redox potential of the HTL is increased. A fluorinated hole- transport polymer with a relatively high oxidation potential (390 mV vs ferrocenium/ferrocene) yielded the device with the highest external quantum efficiency and the longest lifetime under constant current operation. UV cross-linking was optimized to obtain an insoluble hole-transport layer with stable performance. Processing of these materials is compatible with a standard mask aligner used for photolithography. Electroluminescent devices have also been fabricated by spinning a blend of polystyrene and AlQ₃ on top of the crosslinked hole-transport layer.

We demonstrate an efficient organic electroluminescent devices with p-i-n structure. Anamorphous starburst, 4,4',4'-tris(3-methylphenylphenylamino)triphenylamine doped with a strong organic acceptor, tetrafluoro-tetracyano- quinodimethane serves as the p-type hole transport layer, and 4,7-diphenyl-1, 10-phenanthroline doped with Li as the n-type electron transport layer. A breakthrough is achieved in the performances of device based on pure 8-tris- hydroxyquinoline as an emitter: 100cd/m² at 2.52V, 1,000cd/m² at 2.9V and the maximum luminance and efficiency reach 66,000cd/m² and 5.25 cd/A, respectively. The efficiency can be kept above 3cd/A in a very large luminance region from 100 to 55,000cd/m².

We report results of emission measurements from aluminium tris-8-hydroxyquinoline (Alq3) based devices to demonstrate that introducing nanostructure into organic light emitting diodes allows previously trapped modes within the device to be scattered out as far-field radiation. This significantly alters the angular emission pattern and polarization characteristics of the device, and may result in improved device efficiency. The various radiative and non-radiative emission paths have been calculated and used to identify the different modes observed in the emission.

Crystallographic unit cells of vacuum grown ultrathin films of blue-light emitting para-phenylene oligomers on alkali halides, on mica and on Au(111) have been determined via low energy electron diffraction (LEED). On the alkali halides the growth of continuous single crystalline films with either standing or laying molecules dominates. On mica, single-crystalline aggregates (needles) of laying molecules are grown. As the chain length of the molecules increases the mutual order of the needles increases. For p-6P the parallel orientation of the needles is strictly determined by the orientation of surface dipole fields in large dipole domains. A combination of LEED structural results with optical and morphological information from fluorescence microscopy and from atomic force microscopy allows us to deduce subtle details of the organic film aggregates. E.g., bright fluorescence spots could be assigned to nanoscaled gaps in the needles.

In this work we report spectroscopic ellipsometry study of the optical functions of tris (8-hydroxyquinoline) aluminum (Alq₃) thin films on glass substrates in the spectral range from 1.55 eV to 5 eV. Optical functions of Alq3 deposited on unheated substrates and on substrates kept at 100 degree(s)C have been determined. The influence of atmosphere exposure to the optical properties has been investigated. Studies on degradation of OLEDs usually focus on changes due to crystallization of Alq₃ or cathode degradation during operation (in atmosphere or encapsulated). In this work we show that exposure to atmosphere of an Alq3 layer even without deposition of metal cathode results in change of the optical properties of the layer. It has been found that deposition at higher substrate temperature yields improvement in environmental stability of the films, i.e. less decrease of the PL intensity over time with atmosphere exposure, as well as increased PL intensity. Evolution of the optical functions obtained by spectroscopic ellipsometry, absorption, and photoluminescence spectra are presented and discussed.

The polyisocyanate random copolymer containing an asymmetric chiral carbon center and Disperse-Red-1 nonlinear optical chromophores is synthesized. The optical activity is measured at the visible and near infrared spectral ranges, confirming the existence of the induced optical chirality in the copolymer film. Upon the application of a Corona field to the slab waveguide copolymer film, the polarization rotation at the wavelength of 1.3 micrometers is found to be changed, opening the possibility of the chiral electro-optic modulation in a chiral polymeric waveguide thin film.

A highly durable and stable OASLM (Optically-Addressed Spatial Light Modulator) was fabricated with a diarylethene derivative by heating and pressing a dye-dispersed polymer between two flat glass plates in a vacuum. It can be colored and bleached effectively by the visible light irradiation in the ranges of wavelength 400-440nm and 500-600nm, respectively. As a result of the characterization, it was confirmed that this device is durable against 10,000 times iteration of coloring/bleaching and the isomerization state was stably retained in the dark for more than 3months. Since the difference in refractive index between the dye-dispersed polymer and the glass plates is sufficiently small, diffraction at the photochromic layer brought about in the light irradiation can be suppressed. Additionally to small thickness of the photochromic layer (2mm), this will be an important advantage in realizing the high data resolution. Due to the excellent durability and stability, its practical application is expected in the field of data processing requiring both the long-term accumulation of experience and the high-speed parallel operation (i.e. pattern recognition, machine vision and real-time control of robots). Further, this device can readily comply with the multi-device system due to disk layout or cartridge design since the device requires no power supply and its structure is quite simple.

Regarding the characterization of the spatial distribution and the polarization condition of optical field emitted from a probe tip of scanning near-field optical microscope (SNOM), simple and effective evaluation technique is developed. It is realized in connection with the detailed knowledge of photo-induced surface relief formation phenomenon that occurs on the azobenzene functionalized polymer film. Since there was no easy method of evaluating a SNOM probe so far, this could be one of the promising techniques much more convenient than conventional methods. In this report, first the PSR phenomenon is explained and then several examples for the probe evaluation are demonstrated in far- and near-field condition. Furthermore, a trial for nano-patterning and ultra-high density rewritable data storage is performed via scanning near-field optical lithography.

We present a new recorder material, with the possibility to apply to record computer phase holograms, kinoforms, etc. This material is an acrylate monomer with mercapato adhesive, and can be easily to apply for any substrate with out dark room and critical conditions. Due that the absorption spectra from the acrylate monomer adhesive it is localized at UV region (lambda) = 300. We record with lithographic techniques phase grating in this material was made, showing good diffraction efficiency. An important characteristic it is that not necessary the developed process. Our case, the developed processes correspond only the cured polymers process. These properties are attractive due that open the possibility to control the phase material with only to control the cured process. The phase modulation of this material is due by refraction index.

Aluminum compounds comprising of two 2-methyl-8-hydroxyquinolato ligands and one phenolic, naptholic, or other phenolic-based alcohols have been synthesized and studied through literature as electroluminescent materials. This poster reviews two new materials, and suggests a computational model based on AM-1 semi-empirical calculations to predict the electroluminescent wavelength of such materials when incorporated into an Organic Light Emitting Device (OLED).

All-optical poling technique permits purely optical orientation of dye molecules in a polymer film. The experiment includes two phases: the writing (seeding) period and the readout one. In seeding phase two beams, the fundamental (omega) and its second harmonic (SH, 2(omega) ) irradiate the sample and as a result of the coherent interference between them the second order (chi) ⁽²)-susceptibility grating is encoded, with a period satisfying the phase matching condition for SH generation. During the readout step only the fundamental beam is incident onto the material and the second harmonic beam generated by the medium is observed at the back side of the sample. The coherent superposition of two beams at (omega) and 2(omega) frequencies results in a presence of a polar field E(t) inside the material, which can break the centrosymmetry of the medium. The physical origin of the effect lies in the orientational hole-burning in the initially isotropic distribution of dye molecules. It has been demonstrated that efficient all-optical poling requires optimization of relative intensities and relative phase of the seeding beams. An original technique of non-perturbative monitoring of the all-optical poling process without any necessity of taking care of the phase difference between seeding beams is presented. This new technique was applied to several new dye-polymer systems.