Modeling plasmonic efficiency enhancement in organic photovoltaics.

Efficiency enhancement of bulk heterojunction (BHJ) organic solar cells by means of the plasmonic effect is investigated by using finite-difference time-domain (FDTD) optical simulations combined with analytical modeling of exciton dissociation and charge transport efficiencies. The proposed method provides an improved analysis of the cell performance compared to previous FDTD studies. The results of the simulations predict an 11.8% increase in the cell's short circuit current with the use of Ag nano-hexagons.

Optically addressed spatial light modulator with a high photosensitivity and intensity adaptation range.

An optically addressed spatial light modulator based on a single-crystal silicon Schottky diode array photoreceptor and nematic liquid crystals with a high photosensitivity (better than 1microW/cm(2)) and input light intensity adaptation range (greater than 3 orders of magnitude) is demonstrated. This photosensitivity and intensity adaptation range is concurrent with a spatial resolution of 25 line pairsymm, contrast ratios greater than 200:1, and response times less than 10 ms in a wide photosensing wavelength range of 400-1100 nm.

High-resolution liquid-crystal-based spatial light modulator with a thin crystalline silicon photosubstrate structure.

We report an optically addressed, liquid-crystal-based spatial light modulator demonstrating a resolution of 25 line pairs/mm at 50% modulation transfer function and more than 40-line-pair/mm limiting resolution by using a 25-µm-thick silicon Schottky diode-array photosubstrate. This resolution is obtained concurrent with a high photosensitivity of approximately 20 µW/cm(2) and a contrast ratio of over 200:1. The high resolution and photosensitivity obtained with the thin photosubstrate are explained by a fringing field and an equivalent-circuit model, respectively.

Ternary phase and amplitude modulations using a twisted nematic liquid crystal spatial light modulator.

Ternary phase and amplitude modulations that use a reflective mode, 45° twisted nematic liquid-crystal spatial-light modulator are demonstrated. This use offers a simple method for implementation of ternary phase-amplitude filters with high resolution, high optical efficiency, and fast response time.

Introduction to the feature on spatial light modulators and their applications.

The special issue of Applied Optics on spatial light modulators presents a collection of papers that describe improvements in basic devices, smart pixels, and system applications.

Application of a wire-grid-mirror liquid-crystal light valve in a nonlinear joint transform correlator.

We describe the operation of a wire-grid-mirror liquid-crystal light valve and its use for optical pattern recognition. The nonlinear characteristic of the wire-grid-mirror liquid-crystal light valve is used to implement the nonlinear joint transform correlator. Experimental results and computer simulations show that the nonlinear characteristic of the wire-grid-mirror liquid-crystal light valve can produce a well-defined correlation peak and low output background. The performance of the nonlinear joint transform correlator obtained when the wire-grid-mirror liquid-crystal light valve is used is compared with that of the binary joint transform correlator.

Spatial light modulators for optical information processing: introduction by the feature editors.

Some twenty-five papers (including two Letters to the Editor) in this 15 November 1989 issue of Applied Optics consider the technology and use of spatial light modulators. This brief introduction reviews the field.

Near-infrared-to-visible image conversion using a Si liquid-crystal light valve.

A real-time near IR-to-visible image converter using a Hughes silicon liquid-crystal light valve (Si LCLV) has been demonstrated. A 1.06-microm image was converted to a 0.633-microm laser wavelength. The major advantages of this near-IR-to-visible image converter are its high sensitivity, broad bandwidth, coherent- (incoherent-) to-coherent (incoherent) image conversion, up and down wavelength conversion capability, high resolution (>10(5) resolution elements), room-temperature operation, and high damage threshold.

Phase conjugation of low-power optical beans using liquid-crystal light valves.

A real-time hologram generated in the liquid-crystal layer of a leaky-mirror silicon light valve is read by the same low-intensity beams used to record it. For a particular geometry, one of the diffracted beams propagating away from the device is the optical phase conjugate of one of the original beams, thus permitting correction of path-propagation aberrations. Experimental results show correction of tilt, focusing error, and random phase aberrations.

Research on nonlinear optical materials: an assessment.

The seven papers making up this assessment are based on the Workshop on Nonlinear Optical Materials held in April 1986.

Optimal operation temperature of liquid crystal modulators.

This paper describes analyses and confirming experiments on the optimum temperature for fast response in nematic liquid crystal (LC) modulators. It is demonstrated that the LCs or LC mixtures with higher nematic-isotropic phase transition temperatures have higher optimum temperatures and greater potential for improving the figure of merit. Also discussed is the performance of the LC mixture exhibiting optimum temperature at around room temperature.

Pixel-by-pixel array division by optical computing.

An optical system, which divides two arrays in real time, has been conceived and demonstrated for the first time to our knowledge. The pixel-by-pixel division, performed with analog signals, treats two incoherently illuminated arrays in parallel. The configuration used is a feedback arrangement with the data introduced in the loop through two optical image converters (liquid-crystal light valves in our experiments). Analysis of the circuit and experimental results are presented.