We describe devices in which optics and fluidics are used synergistically to synthesize novel functionalities. Fluidic replacement or modification leads to reconfigurable optical systems, whereas the implementation of optics through the microfluidic toolkit gives highly compact and integrated devices. We categorize optofluidics according to three broad categories of interactions: fluid–solid interfaces, purely fluidic interfaces and colloidal suspensions. We describe examples of optofluidic devices in each category.

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Developing optofluidic technology through the fusion of microfluidics and optics

http://antonirogalski.com/wp-content/uploads/2011/12/Infrared-detectors-Status-and-trends.pdf

Infrared detectors: status and trends

Discrete Solitons in Optics

Foreword. Series Editor's Foreword. Preface. 1. Liquid crystal physics.* Introduction.* Thermodynamics and statistic physics.* Orientational order.* Elastic properties of liquid crystals.* Response of liquid crystals to electro-magnetic fields.* Anchoring effects of nematic liquid crystal at surfaces. 2. Propagation of light in anisotropic optical medium.* Electromagnetic wave.* Polarization.* Propagation of light in uniform anisotropic optical media.* Propagation of light in cholesteric liquid crystals. 3. Optical modeling methods.* Jones matrix method.* Mueller matrix method.* Berreman 4x4 method. 4. Effects of Electric field on Liquid Crystals.* Dielectric interaction.* Flexoelectric Effect.* Ferroelectricity in liquid crystals. 5. Freedericksz transition.* Calculus of variation.* The Fredeericksz transition: statics.* The Freedericksz transition: dynamics. 6. Liquid Crystal Materials.* Introduction.* Refractive indices.* Dielectric constants.* Rotational Viscosity.* Elastic constant.* Figure-of-merits.* Refractive index matching between liquid crystals and polymers. 7. Modeling of liquid crystal director configuration.* Electric energy of liquid crystals.* Modeling electric field.* Simulation of liquid crystal director configuration. 8. Transmissive liquid crystal display.* Introduction.* Twisted nematic cells.* In plane switching (IPS) mode.* Vertical alignment (VA) mode.* Multi-domain Vertical Alignment (MVA) Cells.* Optically compensated bend (OCB) cell. 9. Reflective and Trasreflective display.* Introduction.* Reflective liquid crystal displays.* Transflector.* Classification of Transflective LCDs.* Dual-cell-gap Transflective LCDs.* Single-cell-gap Transflective LCDs.* Performance of transflective LCDs. 10. Liquid crystal display matrices, drive schemes and bistable displays.* Segmented displays.* Passive matrix displays and drive scheme.* Active Matrix Displays.* Bistable ferroelectric liquid crystal displays and drive scheme.* Bistable nematic displays.* Bistable cholesteric reflective display. 11. Liquid crystal/polymer composites. * Introduction.* Phase separation.* Scattering properties of liquid crystal/polymer composites.* Polymer dispersed liquid crystals.* Polymer stabilization liquid crystals.* Displays from liquid crystal/polymer composites. 12. Tunable liquid crystal photonic devices. * Introduction.* Laser beam steering.* Variable Optical Attenuators.* Tunable-Focus Lens.* Polarization-Independent LC Devices. Index.

Fundamentals of Liquid Crystal Devices

We present a single disperser spectral imager that exploits recent theoretical work in the area of compressed sensing to achieve snapshot spectral imaging. An experimental prototype is used to capture the spatiospectral information of a scene that consists of two balls illuminated by different light sources. An iterative algorithm is used to reconstruct the data cube. The average spectral resolution is 3.6 nm per spectral channel. The accuracy of the instrument is demonstrated by comparison of the spectra acquired with the proposed system with the spectra acquired by a nonimaging reference spectrometer.

/pdf/single-disperser-design-for-coded-aperture-snapshot-spectral-4q8778zsaj.pdf

Single disperser design for coded aperture snapshot spectral imaging

A transmission-type nonmechanical multiple-angle beam-steering device that uses liquid-crystal blazed grating has been developed. Sixteen steering angles with a contrast ratio of 18 has been demonstrated. A detailed analysis of the liquid-crystal and poly(methyl methacrylate) blazed-grating deflector was carried out to provide guidance during the deflector’s development. A manufacturing offset compensation technique is proposed to improve the device’s performance greatly. A hybrid approach utilizing electrically generated blazed grating combined with the cascading approach described here yields in excess of 500 deflecting angles.

/pdf/liquid-crystal-blazed-grating-beam-deflector-365bfwipz7.pdf

Liquid-crystal blazed-grating beam deflector

We report the first observation of self-trapping of an optical vortex due to the bulk photovoltaic effect. A singly charged vortex nested on a broad cw laser beam is trapped in both transverse dimensions in a lithium niobate crystal. Although the optically induced photovoltaic current is inherently polar, the space charge field gives rise to two-dimensional self-defocusing effects. We observe both circular and elliptical self-trapped vortices, as well as beam deformation due to modulation instability.

Self-trapping of an optical vortex by use of the bulk photovoltaic effect

The properties of convex gratings fabricated by electron-beam lithography are investigated Three grating types are shown The first is a single-panel, true blazed grating in which the blaze angle stays constant relative to the local surface normal This grating provides high peak efficiencies of approximately 88% in the first order and 85% in the second order The second grating has two concentric panels, with each panel blazed at a different angle This type permits flexibility in matching the grating response to a desired form The third type has a groove shape that departs from the sawtooth blazed profile to increase the second-order bandwidth All these types are difficult or impossible to produce with conventional techniques The gratings compare favorably with conventional (holographic and ruled) types in terms of efficiency and scatter Simple scalar models are shown to predict the wavelength response accurately These gratings allow the optical designer to realize fully the considerable advantages of concentric spectrometer forms

Convex grating types for concentric imaging spectrometers.

We have constructed a computed-tomography imaging spectrometer that uses a phase-only computer-generated hologram (CGH) array illuminator as the disperser. This imaging spectrometer collects multiplexed spatial and spectral data simultaneously and can be used for flash spectral imaging. The CGH disperser has been designed to maintain nearly equal spectral diffraction efficiency among a 5 x 5 array of diffraction orders and to minimize diffraction efficiency into higher orders. Reconstruction of the (x, y, lambda) image cube from the raw, two-dimensional data is achieved by computed-tomography techniques. The reconstructed image and spectral-signature data compare favorably with measurements by other spectrometric methods.

/pdf/demonstration-of-a-computed-tomography-imaging-spectrometer-1z359zh48c.pdf

Demonstration of a computed-tomography imaging spectrometer using a computer-generated hologram disperser.

We report results from a field demonstration of a nonscanning high-speed imaging spectrometer [computed-tomography imaging spectrometer (CTIS)] capable of simultaneously recording spatial and spectral information about a rapidly changing scene. High-speed spectral imaging was demonstrated by collection of spectral and spatial snapshots of a missile in flight. This instrument is based on computed-tomography concepts and operates in the visible spectrum (430–710  nm). Raw image data were recorded at video frame rate (30  frames/s) and an integration time of 2  ms. An iterative reconstruction of the spatial and spectral scene information from each raw image took 10  s. We present representative missile spectral signatures from the missile firing. The accuracy of the high-speed spectrometer is demonstrated by comparison of extended-source static-scene spectra acquired by a nonimaging reference spectrometer with spectra acquired by use of CTIS imaging of the same static scenes.

/pdf/demonstration-of-a-high-speed-nonscanning-imaging-18kj34cag9.pdf

Paul D. Maker

Papers

Liquid-crystal blazed-grating beam deflector

Self-trapping of an optical vortex by use of the bulk photovoltaic effect

Convex grating types for concentric imaging spectrometers.

Demonstration of a computed-tomography imaging spectrometer using a computer-generated hologram disperser.

Demonstration of a high-speed nonscanning imaging spectrometer