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Collagen is a biological macromolecule capable of second harmonic generation, allowing label-free detection in tissues; in addition, molecular orientation can be determined from the polarization dependence of the second harmonic signal. Previously we reported that in-plane orientation of collagen fibrils could be determined by modulating the polarization angle of the laser during scanning. We have now extended this method so that out-of-plane orientation angles can be determined at the same time, allowing visualization of the 3-dimensional structure of collagenous tissues. This approach offers advantages compared with other methods for determining out-of-plane orientation. First, the orientation angles are directly calculated from the polarimetry data obtained in a single scan, while other reported methods require data from multiple scans, use of iterative optimization methods, application of fitting algorithms, or extensive post-optical processing. Second, our method does not require highly specialized instrumentation, and thus can be adapted for use in almost any nonlinear optical microscopy setup. It is suitable for both basic and clinical applications. We present three-dimensional images of structurally complex collagenous tissues that illustrate the power of such 3-dimensional analyses to reveal the architecture of biological structures.

Changes in the transit time of a short electrical pulse propagating through a coplanar transmission line (CTL) are used to sense protein interactions at an aqueous–solid interface. The effective permittivity of the CTL is lowered as a result of protein binding at the interface. This decrease is sensed by the relative decrease in propagation transit time of a baseband picosecond electrical pulse through the probe. It is shown that the microwave probe is sensitive to protein binding at a liquid–solid interface and can be used for measuring dissociation constants in the nM range. In comparison with previous microwave sensors, this sensor is relatively insensitive to temperature fluctuations. It has the capability of operating in non-optical environments such as porous capillaries, capillaries filled with separation media, or opaque substrates.

Using the method proposed by Swanepoel (J Phys E: Sci Instrum 17:896–903, 1984), a-Si:H and nc-Si:H thin films have been successfully characterised using the transmission spectrum alone as taken in the UV–visible range. The studied samples were deposited on both Corning glass and Polyethylene napthalate (PEN) substrates using the Hot Wire Chemical Vapour deposition technique (HWCVD). Results on refractive index, absorption coefficient and energy gap will be presented. Thicknesses calculated by the same method will be compared to those obtained by direct measurement using a Dektak profilometer.

The displacement of water from a solid–aqueous interface by a low-dielectric constant film that is a few nanometers thick can be detected as a change in the transit time of a baseband electrical pulse, of picosecond duration, propagating in a coplanar transmission line. The results of an electromagnetic analysis are experimentally verified by depositing polyelectrolyte monolayers on the probe surface and measuring changes in the pulse transit time of a short baseband electrical pulse.

The residual strain in a-Si:H layers has been determined directly using synchrotron radiation diffraction, at LNLS in Brazil, by two different methodologies. Using a method previously presented using laboratory X-ray sources, the height and length of side of the Si–Si 4 tetrahedron are determined from variations in the diffraction angle of the first two amorphous peaks. In a more extensive calculation, the spatially dependent pair correlation function is calculated, allowing the separation of strain resulting from changes in the bond length and the bond angle. Two different layers, deposited by HW-CVD on glass substrates at growth temperatures of 300 and 500 °C, have been studied to investigate the effect of growth temperature on residual stress.

The microstructure and optical properties of a series of hydrogenated amorphous silicon layers deposited on glass substrates at different temperature have been characterized by means of X-ray diffraction techniques and optical spectroscopy. The radial distribution function of the as-deposited samples showed an increase in the bond angle and a decrease in the radial distance indicating a relaxation of the amorphous network with increasing the deposition temperature. Light induced degradation was studied using a simulated daylight spectrum. The changes in hydrogen bonding configuration, associated with the light soaking at different stages of illumination, was monitored via the transmission bands of the vibrational wag and stretch modes of the IR spectrum.

A method is presented that incorporates thin, lossy layers into a finite-difference frequency-domain algorithm designed for structures with circular geometry. The method allows the grid spacing to be much larger than the thickness of the thin layers. This greatly reduces the computational effort required when simulating circular structures such as optical fibers that incorporate thin layers. The method is validated by a comparison with the analytical solutions. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 453–457, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21378

The effect of light-soaking, using a simulated daylight spectrum (colour temperature 5800 K) on the crystallinity, defect structure, and total hydrogen concentration of a-Si:H grown by HW-CVD is being investigated in an ongoing project. In this article, positron beam based electron momentum spectroscopy is applied to monitor the evolution of the open-volume defect structure after each illumination stage. The results indicate an initial increase in free volume at dangling-bond complexes on illumination, with no indication of a change in defect concentration or generation of larger microvoids. On further illumination, there is a reduction in the low electron momentum fraction, which is not accompanied by a similar change in the free-volume. This can be interpreted as a reconfiguration of the hydrogen in the dangling-bond complex, followed by its release into a mobile state.

A self-contained experimental technique is proposed for measuring the absolute optical absorption spectra, thermal diffusivity, and thermal conductivity of polymer thin films. The technique is based on photothermal deflection spectroscopy and provides sensitivity that is high enough to quantify the very small optical absorption losses in polymer films used for optical waveguide applications. The capabilities of the technique are demonstrated with measurements performed on thin films of poly(methyl methacrylate) and a fluorinated polymer (CYTOP). An error analysis is presented, and the factors are discussed that influence the accuracy of the technique. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2717–2726, 2001

Electrooptic modulators that consist of an optical fiber waveguide coupled to an electrooptic waveguide are reviewed. Desirable attributes of these devices are that the optical fiber is uninterrupted and the interaction with the electrooptic region occurs only where the optical properties are modulated. In this paper we review in-line fiber evanescent field modulators that we have implemented with electrooptic polymers and compound semiconductor quantum wells. We show that the beam propagation method can accurately simulate the behavior measured in these devices.

The transfer function of an external modulator is the critical factor that determines the spurious free dynamic range, signal power gain, and noise figure of a wide-band analog RF-photonic link. We present an in-line asymmetric directional coupler modulator with distributed optical loss capable of providing a transfer function linearized to the fourth order for multioctave bandwidths. This modulator compares favorably with multiple modulator suboctave linearization techniques consisting of series symmetric directional coupler and series Mach-Zehnder modulators and superoctave parallel Mach-Zehnder, and cascaded sections containing series Mach-Zehndersymmetric directional coupler modulators. The optimum bias point for the asymmetric directional coupler modulator is determined by device dimensions and material parameters with relative insensitivity to errors introduced during fabrication. Optical insertion loss imposes significant limitations on modulator performance. An implementation of an in-line asymmetric directional coupler modulator is discussed that eliminates excess loss due to fiber coupling in order to achieve a large RF power gain and competitive noise figure compared to the linearization configurations.

Second harmonic generation of ultrashort pulses in first- and higher-order quasi-phase-matched nonlinear structures is investigated theoretically. It is shown that using such structures high conversion efficiency can be achieved while preserving the ultrashort pulse duration. Using periodically poled bulk lithium niobate as an example, it is found that nearly complete conversion of a 900 nm wavelength 100 fs pulse to the second harmonic may be possible in a first-order structure without any broadening of the pulse width.

Methods to optimize the generation of ultrashort second harmonic pulses are investigated. The goal is to maximize the conversion efficiency while maintaining a short pulse. The first method exploits the effects of anomalous-dispersion phase-matching. In a nonlinear polymer we show that an optimum concentration of chromophore exists that maximizes the conversion efficiency without causing unacceptable pulse-spreading. In the second method we use unipolar and bipolar quasi-phase-matched (QPM) structures to increase the nonlinear interaction length. Unipolar and bipolar QPM structures not only provide significant enhancement in ultrashort pulse second harmonic generation but also reduce the pulse distortion.

The microfabricated surface plasmon sensor is a hybrid system that integrates optical, mechanical and electronic components. The sensor contains elements that are common to numerous electro-optical systems, creating a miniature optical bench. The microsystem elements include a single-mode optical fiber, a graded index collimating lens, a scanning rotating micro-mirror, a cavity filled with index matching fluid, and a position sensitive photodiode. The elements are both laterally and vertically aligned using multi-substrate bonding and positive component-to-component alignment.

We describe the fabrication and performance of a thin-film electro-optic Fabry-Perot modulator operating in reflection, at wavelengths compatible with silicon detectors, fabricated on a silicon substrate. A nonlinear polymer is used with a low dielectric constant that permits an electrical bandwidth in excess of 100 MHz with low modulating energy. Existing thin-film fabrication techniques and materials are used to demonstrate device performance. We report modulation of approximately 1.5% and describe foreseen improvements in nonlinear polymers and technology which promise in excess of 5% modulation with a 5 V modulating voltage. >

The authors describe a self-homodyne technique to measure the modulation efficiency of an optical phase modulator. The phase modulator is driven by a sine wave and the baseband spectrum is measured and analyzed. Combinations of the ratio of harmonics are used to estimate V/sub /spl pi// of a commercially available modulator with a resolution of 0.8%. The method offers simplicity because it uses a single laser, does not require sensitive optical adjustments, and lends itself to the measurement of V/sub /spl pi// as a function of modulation frequency and optical carrier wavelength.

It is demonstrated that surface plasmon sensing can be performed in the shot-noise-limited regime to resolve index of refractive changes on the order of 10sup-10/sup/√Hz at input powers of 1 mW. This improved resolution is achieved by using active electronic noise cancelling to suppress laser intensity noise and a wavelength that maximizes sensitivity to index of refraction changes occurring at an interface. The resolution of the system is experimentally demonstrated by measuring the refractive index change of air in response to pressure changes.

A simple analysis is presented of reflectance from a stratified uniaxial media with the optic axes parallel or perpendicular to the plane of incidence.

We report the observation of electrically induced changes in transmissivity in Fabry-Perot devices consisting of spin-cast azo-dye/polymer films deposited between gold mirrors. In poled samples the observed modulation shows a linear dependence on the applied modulating voltage. The ratio of the transmissivity modulation observed using incident transverse magnetic polarization to that observed using transverse electric polarization is used to demonstrate that the electrooptic effect dominates the modulation. This is, to our knowledge, the first reported use of a polymeric thin film linear electrooptic material in a Fabry-Perot structure and demonstrates the use of etalons to enhance electrooptic effects in very thin films.

A solgel process is described to produce Ta(2)O(5) films as short wavelength antireflective (AR) coatings for silicon. The AR coatings were optimized for 370 nm by controlling the acid catalyzed hydrolysis of Ta(OC(2)H(5))(5), the spin coating parameters, and the heat treatment process (rapid thermal processing (RTP) and muffle furnace). Film thickness uniformity across the wafer was better than 1%, and all the coatings tested passed the standard scotch tape test before and after heat treatment and exhibited no change in optical properties after submersion in liquid N(2). Several heat treatment protocols for densifying the films were studied. Spin coated films heat treated in a muffle furnace at 275 degrees C yielded Ta(2)O(5) AR coatings that reduced the reflectance losses from silicon at 370 nm by 86%, the reduction being within 1% of the theoretical value. Films subjected to RTP at temperatures ranging from 300 to 1000 degrees C reduced the reflectance loss in some cases by as much as 95%. The results demonstrate that spin coated solgel derived Ta(2)O(5) films subjected to a low temperature (300 degrees C) heat treatment can form durable films suitable for near UV AR coatings for high index silicon devices, such as charge couple imagers and photovoltaic cells.

Calcul de la dispersion de la vitesse de groupe dans les guides d'onde multicouches asymetriques a fort guidage

A rigorous theory describing the diffraction of light by a muscle fibre has been formulated. The basis of this analysis is the rigorous coupled-wave approach of T. K. Gaylord & M. G. Moharam (Proc. IEEE 73, 894 (1985)); however, we obtain here a closed-form analytical result that is both mathematically simple and physically easy to understand. We have compared our results on striated muscle fibres with the analytical results obtained by A. F. Huxley (Proc. R. Soc. Lond. B 241, 65 (1990)) using the normal mode approach, and with those obtained by R. A. Thornhill, N. Thomas & N. Berovic (Eur. Biophys. J. 20, 87 (1991)) using a multiwave first-order coupled-wave approximation. For an equivalent set of assigned fibre parameters, our results are consistent with these mentioned. Extension of this analysis to a fibre with different structures showed that the differences in diffraction efficiencies of different orders for a frog skeletal fibre and for an insect flight fibre are clear; the sensitivity to distinct structural organization of the fibre is very good.

The complete synthesis and characterization of a poly(methyl methacrylate-co-couma-romethacrylate) is described. Thin films of this polymer were corona-poled and aged under various conditions. The intensity of second harmonic light, generated by passing a laser beam through the polarized films, indicated the average degree of dipole alignment in the films as a function of time and temperature. The long-term aging data were fit with biexponential and stretched exponential equations. A model based on diffusion of defects (holes) in a locally heterogeneous glassy matrix is discussed

A 2.5- mu m-thick corona-poled copolymer film was used to double approximately 13-fs-long, 50-nJ-energy, 625-nm-wavelength pulses at a 8-kHz repetition rate. The large effective d coefficient results in a relatively high conversion efficiency for such a thin film. A maximum efficiency of 0.13% has been measured. Long-term stable operation was obtained with efficiencies of 0.025% at the damage threshold of approximately 160 GW/cm/sup 2/. The damage threshold is remarkably high for organic materials and was found to be peak intensity rather than average intensity dependent. >

A method is presented to measure the dielectric properties of a thin film over a broad microwave frequency range. The parallel-plate transmission line geometry offers both the advantages of pronounced sensitivity to thin-film properties and exact computation of the value of the dielectric constant and the loss tangent. With multiline thru-reflect-line calibration techniques, the dielectric constant and loss tangent are determined to an accuracy better than 4% at 10 GHz.

Ultrashort-pulse (

Electro‐optic properties of thin polymeric films can be studied by incorporating the films into the spacer layers of transmission‐mode Fabry–Perot devices formed using metal mirrors. The metal mirrors, which also serve as electrodes, are used for the application of an electric field for poling the polymeric material and for subsequently modulating the index of refraction through the electro‐optic effect. A model for transmission modulation is developed, and experimental characterization of the devices by angles tuning at a fixed wavelength is presented. Suitable approximations can be made to allow determination of the net trapped charge and the electro‐optic coefficients of the spacer layer. This paper demonstrates the use of polymeric thin‐film etalon devices for the study of new materials and indicates their potential use as electro‐optic devices.

Second-order nonlinear optical properties of newly designed and synthesized coumaromethacrylate side-chain polymers are reported. The optimum poling conditions were determined experimentally. The optimum poling temperature for these side-chain polymers is well above the glass transition temperature. The second harmonic coefficient of films poled by coronaonset at elevated temperature and the linear electro-optic coefficient of films poled by contact electrodes were measured. The stabilized value of the second harmonic coefficient, d33, at 1064nm fundamental wavelength was found to be 13 pm/V. The linear electro-optic coefficient, r33, exhibits strong dispersion ranging from 2 to 12pm/V in the wavelength range 477 to 1115 nm.

We demonstrate a GaAs/AlGaAs multiple-quantum-well in-line fiber optic intensity modulator. Based on evanescent wave coupling between a GaAs/AlGaAs multiple-quantum-well waveguide and a single-mode fiber, this device concept combines the inherent advantages of in-line fiber devices with high-speed GaAs integrated optoelectronics. The GaAs waveguide uses distributed Bragg mirror layers to phase match to the low-index fiber. Intensity modulation of the transmitted light through the fiber is achieved by tuning the effective propagation index of the GaAs waveguide via the quantum-confined Stark effect. Initial structures show a modulation contrast (ΔT/T) of more than 53%, with an applied voltage of 5 V.

Transverse and axial trapping forces are calculated in the ray optics regime for a multiple-beam fiber-optic light-force trap for dielectric microspheres located both on and off axis relative to the beam axis. Trap efficiencies are evaluated as functions of the effective index of refraction of the microspheres, normalized sphere radius, and normalized beam waist separation distance. Effects of the linear polarization of the electric field and of beam focusing through microlenses are considered. In the case of a counterpropagating two-beam fiber-optic trap, using microlenses at the distal ends of the fiber to focus the beams may somewhat increase the trapping volume and the axial stability if the fiber spacing is sufficiently large but will greatly reduce the stiffness of the transverse force. Trapping forces produced in a counterpropagating two-beam fiber-optic trap are compared with those generated in multiple-beam fiber-optic gradient-force traps. Multiple-beam fiber-optic traps use strong gradient forces to trap a particle; therefore they stabilize the particles much more firmly than do counterpropagating two-beam traps.

Polysiloxane and conductive polymers were integrated onto a side-polished optical fiber to implement a variable optical attenuator. A conductive polymer thermo-optically altered the refractive index of elastomer placed in close proximity to a fiber core.

Transitions in order/disorder phase states of biological tissues were analyzed using polarization modulated second harmonic generation imaging. The degree of structural disorder was significantly correlated with severity of pathological changes.

The noncentrosymmetric molecular structures responsible for the second order nonlinear effects of collagen fibrils are identified by sum frequency vibrational spectroscopy. CH 2 and C=O functional groups dominate the achiral and chiral spectra, respectively.

An experimental method for quantifying disorder within the anulus fibrosus is described based on polarization-modulated second harmonic generation imaging (PM-SHG-I). This method is demonstrated by imaging the anular lamellar architecture of a mouse model of compressive loading. Results were consistent with those obtained in an earlier study where organization was quantified directed secants image analysis on photomicrographs. In this study the orientation within individual lamellia is quantified by average orientation of the collagen molecules within a defined volume of a single lamellar as measured by the PM-SHG-I. Lamellar boundaries can be identified through the SHG intensity images, and confirmed through co-registration with photomicrographs of the same region. The orientation within the lamellar is quantified by the polarization angle of the maximum second harmonic intensity. PM-SHG-I offers several advantages as compared with the method of directed secants: first, it is nondestructive, allowing repeated measurements of the same tissue; second, images are captured on the order of seconds and capable of obtaining information up to a depth of 200-300 microns, thus allowing for real-time assessment of load damage; third, organization is measured at a much higher resolution, as it is based on disorder within the molecular arrays of a single lamella.

Minimizing pulse-spreading caused by group velocity mismatch demands structures that achieve large conversion efficiency with a short interaction length. Optimized femtosecond-pulse generation in quasi-phase-matched thin-film structures will be discussed. >

We discuss the molecular engineering of a second order nonlinear optical (NLO) polymer materials specifically for ultrashort optical pulse diagnostics. We use second harmonic generation (SHG) frequency resolved optical gating (FROG) to measure the amplitude and phase of an ultrashort pulse. It is shown that thin poled TCV/PMMA are sufficiently nonlinear and robust to be used in Ti:Sapphire ultrashort pulse diagnostics. Since such thin NLO films are not limited by phasematching they hold great promise for extremely short pulse diagnostics.

Summary form only given. The distortion of an ultrashort pulse from propagation in a linear dispersive medium is well-understood. Not so understood are the distortions which occur when ultrashort optical pulses are generated in the dispersive medium by a nonlinear interaction. This talk will focus on second harmonic generation (SHG), where it is well-known that the second-harmonic (SH) pulse shape differs from the fundamental even for long pulses. This talk will focus on additional pulse distortions important when undistorted ultrashort pulses must be generated as efficiently as possible.

An in-line fiber modulator is an asymmetric directional coupler consisting of a continuous single mode fiber interacting through the evanescent fields with an electro-optic (EO) waveguide. Such an asymmetric coupler can be described by coupled wave theory.

A radio frequency (RF) modulated optical fiber link is an attractive alternative to coaxial cables to distribute large bandwidth analog RF signals. A critical component necessary for applications such as antenna remoting is a fiber optic modulator with a large dynamic range. The dominant modulator in use today is the Mach-Zehnder which requires linearization schemes to achieve a large dynamic range. We present an alternative modulator configuration which can be tuned to an operating point where the second, third, and fourth order intermodulation products are minimized, thus yielding a large dynamic range without linearization schemes. This inline fiber modulator consists of an electro-optic (EO) waveguide deposited directly onto single mode fiber half coupler block.

A technique based on photothermal deflection spectroscopy has been developed for measuring the absolute absorption of polymers. The technique utilizes the frequency dependence measurement of the deflection signals to retrieve polymers' thermal properties and experimental parameters that are necessary to convert the deflection signals to the absolute absorption coefficients. All the measurements are done on the same experimental setup and the same sample without the need of obtaining either the materials' thermal properties or the reference absorption coefficients from other sources. This technique has been applied to several polymers and the results are reported.

A Newton-Raphson complex root-finding algorithm, based on the thin-film transfer matrix analysis, is described. This second-order convergent algorithm, which requires only O(n) calculations per iteration, was presented to find the complex propagation constants of any mode in an n-layer planar waveguide. The number of calculations per iteration is reduced below those required by competitive schemes through application of the Cauchy-Riemann relations. The method demonstrates higher accuracy and improved efficiency over other iterative techniques, making this approach highly suitable for the analysis and design of planar structures consisting of a large number of layers. >

We demonstrate a GaAs/AlGaAs multiple-quantum-well in-line fiber optic intensity modulator. Based on evanescent wave coupling between a GaAs/AlGaAs anti-resonant reflective optical waveguide and a side-polished single mode fiber, this device concept combines the inherent advantages of in- line fiber devices with high-performance GaAs integrated optoelectronics. The GaAs waveguide utilizes distributed Bragg reflector mirrors, which are designed to provide maximum reflection at a given more angle, to phase-match to the low-index fiber. Intensity modulation of the transmitted light through the fiber is achieved by changing the complex propagation constant of the GaAs waveguide through the quantum-confined Stark effect. Typical device shows an on/off ratio of 4:1, with an applied voltage of 9V. Calculations show that with a longer interaction region, an on/off ratio of more than 40dB is achievable with the same applied voltage.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A GaAs/AlGaAs in-line fiber optic filter for wavelength division multiplexing applications is demonstrated. The device consists of a GaAs/AlGaAs anti-resonant reflecting optical waveguide (ARROW) evanescently coupled to a single mode fiber. At certain discrete wavelengths, light is coupled from the fiber to the ARROW, due to phasematching conditions. Sharp resonances are observed around the design wavelength of 830 nm. The 3 dB cutoff bandwidth for TE polarization is 0.5 nm and the rejection ratio is 9 dB.

High-frequency instrumentation was acquired to perform: (a) high-frequency dielectric measurements on poled electro-active polymers and to determine the stability when exposed to microwave radiation, and (b) electro-optic measurements of the resonant enhancement of nonlinear polymers with demonstrated photochemical stability. In particular, the equipment was used to investigate large-bandwidth, traveling wave polymeric in-line fiber (PILF) modulator that is being co-developed by UC Davis and Optivision. This PILF amplitude modulator consists of a fiber half-coupler substrate evanescently coupled to a multimode electro-optic waveguide. PILF modulators are intrinsically rugged, exhibit low third order intermodulation nonlinearity and can be produced at lower cost than fiber pigtailed modulators. The equipment consisted of a high-frequency probe station, high-frequency amplifier and signal generator, 15 GHz photodetector, low relative intensity noise fiber coupled 1330 nm laser, and a 1064 diode pumped laser. The deviations from the original budget are that the $30K in UC cost sharing was used towards a laser ablation accessory for the probe station (instead of the thermal evaporator), the elimination of the 1550 nm laser source and the purchase with fund remaining a high-frequency signal generator.

Summary form only given. We have demonstrated an inline fiber optic filter using a GaAs ARROW waveguide as the overlay. It has a rejection ratio of 11 dB and a bandwidth of 7 nm. The inclusion of quantum wells in the waveguide core will lead to a new class of integrated fiber devices, including modulators, detectors, amplifiers, and lasers.

We are developing a traveling electro-optic modulator for analog microwave modulated fiber optic links used in radar applications. The modulator is a polymer in-line fiber device that has a rugged and low loss interface to single mode fibers and can be engineered to provide linear modulation over a large dynamic range. In the development of the modulator we take advantage of a variety properties available in polymers. The ability to deposit a conformal electro-optic thin film is used to fill the gaps between high-frequency co-planar electrodes and thus obtain a good overlap between the electric field produced by the the microwave electrodes and the fields in the optical fiber and the electro-optic waveguide. Reactive ion etching of the electro-optic polymer is used to trim the thickness of the polymer waveguide to obtain operation at a specific wavelength. The thermo-optic effect is used to fine tune the operation point of the modulator to obtain a large dynamic range. The geometry of the modulator permits operation close to the absorption peak of the electro-optic polymer and this provides the opportunity to take advantage of the resonant enhancement of the nonlinearity in the vicinity of an absorption band.

A micromachined optical 'trap' to capture and move micron sized dielectric particles is presented. The trap consists of four single mode optical fibers mutually aligned to have a common optical beam intersection at the center of a micromachined housing. The intersection of the beams forms an optical 'cross-hair' which captures dielectric microparticles with a strong optical gradient force field, and holds them for further manipulation, visualization, and/or analysis. The stability and magnitude of the trapping force fields are comparable to the single beam 'optical tweezers' technique, but are considerably more versatile.

Summary form only given. We demonstrate the application of decal technique to electro-optic modulators. It allows the deposition of high-quality, corona-poled, nonlinear polymer films onto structures without subjecting them to spin coating, large electrostatic fields, and other nonlinear polymer processing steps that may damage the underlying device. Another distinct advantage of the decal deposition for devices where the film thickness determines the optical spatial resonances, such as Fabry Perot structures or waveguides, is that the thickness of the film is determined prior to deposition on the final substrate and since many identical patches are formed it ensures reproducibility between devices. The decal deposition technique significantly simplifies the fabrication of the in-line fiber electro-optic modulators.

Summary form only given. We have designed and fabricated a polymeric in-line fiber modulator using novel fabrication techniques. This device is based on evanescent coupling from a fiber half-coupler to a nonlinear polymer waveguide and takes advantage of a unique polymer deposition process.