This paper describes the fundamentals of phase-only liquid crystal on silicon (LCOS) technology, which have not been previously discussed in detail. This technology is widely utilized in high efficiency applications for real-time holography and diffractive optics. The paper begins with a brief introduction on the developmental trajectory of phase-only LCOS technology, followed by the correct selection of liquid crystal (LC) materials and corresponding electro-optic effects in such devices. Attention is focused on the essential requirements of the physical aspects of the LC layer as well as the indispensable parameters for the response time of the device. Furthermore, the basic functionalities embedded in the complementary metal oxide semiconductor (CMOS) silicon backplane for phase-only LCOS devices are illustrated, including two typical addressing schemes. Finally, the application of phase-only LCOS devices in real-time holography will be introduced in association with the use of cutting-edge computer-generated holograms. The capabilities and applications of phase-only liquid crystal on silicon (LCOS) technology are reviewed by scientists in China and the United Kingdom. Zichen Zhang and co-workers from Tsinghua University in Beijing and the University of Cambridge describe how an electronically controlled liquid-crystal pixel array on a silicon backplane can be useful for manipulating the phase of coherent light. Such LCOS phase modulators have many potential applications, including real-time holography, head-up displays, wavelength-selective switches and reconfigurable optical add-drop multiplexers. Commercial devices currently offer array sizes of up to about 1-inch diagonal with pixel pitches in the range 6–20 μm. However, the technology is still immature; the liquid-crystal materials and silicon control backplane need to be optimized in order to realize the potential of such devices.

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Fundamentals of phase-only liquid crystal on silicon (LCOS) devices

Ultrafast laser nanostructuring of photopolymers: a decade of advances

This paper introduces xurography, or "razor writing," as a novel rapid prototyping technique for creating microstructures in various films. This technique uses a cutting plotter traditionally used in the sign industry for cutting graphics in adhesive vinyl films. A cutting plotter with an addressable resolution of 10 /spl mu/m was used to cut microstructures in various films with thicknesses ranging from 25 to 1000 /spl mu/m. Positive features down to 35 /spl mu/m and negative features down to 18 /spl mu/m were cut in a 25 /spl mu/m thick material. Higher aspect ratios of 5.2 for positive features and 8 for negative features were possible in a 360 /spl mu/m thick material. A simple model correlating material properties to minimum feature size is introduced. Multilayered microstructures cut from pressure sensitive and thermal activated adhesive films were laminated in less than 30 min without photolithographic processes or chemicals. Potential applications of these microstructures are explored including: shadow masking, electroplating, micromolds for PDMS, and multilayered three-dimensional (3-D) channels. This inexpensive method can rapidly prototype microfluidic devices or tertiary fluid connections for higher resolution devices. [1488].

Xurography: rapid prototyping of microstructures using a cutting plotter

True-3D imaging and display systems are based on physical duplication of light distribution. Holography is a true-3D technique. There are significant developments in electro-holographic displays in recent years. Liquid crystal, liquid crystal on silicon, optically addressed, mirror-based, holographic polymer-dispersed, and acousto-optic devices are used as holographic displays. There are complete electro-holographic display systems and some of them are already commercialized.

/pdf/state-of-the-art-in-holographic-displays-a-survey-n3s3z5orxh.pdf

State of the Art in Holographic Displays: A Survey

Fabrication of 3D Biocompatible/Biodegradable Micro-Scaffolds Using Dynamic Mask Projection Microstereolithography

A novel high-accuracy microstereolithography method employing an adaptive electro-optic mask

We report the development of a new microstereophotolithography technique for creation of three-dimensional microcomponents by use of a planar, layer-by-layer process of exposure, in which a spatial light modulator is used as a dynamic lithographic mask. The system operates in the UV to take advantage of the wide supply of commercially available photopolymers designed for conventional stereolithography. With this novel procedure it is possible to build components with feature sizes as small as a few micrometers. The experimental setup is briefly described, and the first microcomponent fabricated by this system is shown.

Microfabrication by use of a spatial light modulator in the ultraviolet: experimental results.

http://users.sussex.ac.uk/~tafj0/papers/OC_fully.pdf

Fully complex optical modulation with an analogue ferroelectric liquid crystal spatial light modulator

We present a method of producing a computer-generated hologram by use of a zero-twist linear nematic liquid-crystal spatial light modulator. A 2×1 macro pixel method is used; one pixel represents the real data, and one, the imaginary. A method is shown that produces both positive and negative analog amplitude modulation.

/pdf/two-pixel-computer-generated-hologram-with-a-zero-twist-2vedlsjyoz.pdf

Two-pixel computer-generated hologram with a zero-twist nematic liquid-crystal spatial light modulator

A method of producing an arbitrary complex field modulation by use of two pixels of an analog ferroelectric spatial light modulator (SLM) is demonstrated The method uses the gray-scale modulation capabilities of a SLM to spatially encode the complex data on two pixels A spatial filter is used to remove the carrier signal This technique gives fast gray-level amplitude and phase modulation

David M. Budgett

Papers

A novel high-accuracy microstereolithography method employing an adaptive electro-optic mask

Microfabrication by use of a spatial light modulator in the ultraviolet: experimental results.

Fully complex optical modulation with an analogue ferroelectric liquid crystal spatial light modulator

Two-pixel computer-generated hologram with a zero-twist nematic liquid-crystal spatial light modulator

Dynamic complex wave-front modulation with an analog spatial light modulator.