J. I. Thackara

Poled electro-optic waveguide formation in thin-film organic media

We describe a novel technique for the fabrication of electro‐optic (EO) waveguides in integrated optic device structures employing organic EO materials. The technique combines the poling and waveguide formation steps by utilizing patterned poling electrodes and the induced birefringence associated with the poling process. Several prototype waveguide devices fabricated using this procedure are reported.

Photoaddressed liquid crystal spatial light modulators

The general problems and limitations of photoaddressed liquid crystal spatial light modulators (SLMs) are discussed, and experimental results are presented. A GaAs wafer photoaddressed nematic liquid crystal SLM is described in detail with experimental results. The edge enhancing or differentiating SLM is discussed, and the results of GaAs photoaddressing are reported. The preliminary experimental behavior of photoaddressed ferroelectric liquid crystal SLMs is described.

Ferroelectric liquid-crystal devices and optical processing

Abstract The application of ferroelectric liquid-crystal devices to optical processing is discussed. Our current activity in silicon photoaddressed ferroelectric liquid-crystal spatial light modulators is reported.

Photoaddressed liquid crystal edge-enhancing spatial light modulator.

Pattern recognition via optical correlation generally requires an incoherent-to-coherent input image converter and benefits from edge enhancement of the input image. We have created a photoaddressed nematic liquid crystal differentiating spatial light modulator that fulfills both these functions. Developments in photoaddressing are discussed, and experimental results on edge enhancement are presented.

Organic Electro-Optic Waveguide Modulators And Switches

Organic and polymeric materials exhibit many important properties as electro-optic materials. Poled polymer films are particularly well suited for integrated optic devices, due to their large electro-optic coefficients, low dielectric constants, and flexible processability. We review our work toward the fabrication of active polymer integrated optic devices based on a newly developed channel waveguide fabrication procedure, and detail some of the properties of the devices.

Advances In Organic Electro-Optic Devices

Organic and polymeric materials have many useful features for thin-film electro-optic devices. These include low dielectric constants, moderate-to-large electro-optic coefficients, and low optical loss. This paper presents a review of the useful features of organic materials for device applications, summarizes the current optical response levels of some organic materials, and describes the performance of several device prototypes fabricated from poled organic films.

Fast Nematic Liquid Crystal Spatial Light Modulator

Electra-optic shutters that operate at a kilohertz rate have been demonstrated with nematic liquid crystals operated in the surface-mode or π-cell configuration. This principle has been employed to fabricate an NLC photoaddressed spatial light modulator that is faster than twisted-nematic devices.

Organic Integrated Optical Devices

Organic and polymeric materials have emerged in recent years as promising candidates for advanced device and system applications1–4. This interest has arisen from the promise of extraordinary optical, structural, and mechanical properties of certain organic materials5–12, and from the fundamental success of molecular design13–15 performed to create new kinds of materials. From an optical standpoint, organics offer temporal responses ranging over fifteen orders of magnitude, including large nonresonant electronic nonlinearities (fsec-psec), thermal and motional nonlinearities (nsec-msec), configurational and orientational nonlinearities (msec-sec), and photochemical nonlinearities (psec-sec). Additionally, organic and polymeric materials can exhibit high optical damage thresholds, broad transparency ranges, and can be polished or formed to high-optical quality surfaces. Structurally, materials can be made as thin or thick films, bulk crystals, or liquid and solid solutions, and can be formed into layered film structures, with molecular engineering providing different optical properties from layer to layer. Mechanically, the materials can be strong and resistant to radiation, shock, and heat. When coupled with low refractive indices and low D.C. and microwave dielectric constants, the collective properties of these extraordinary materials show great promise towards improving the performance of existing electro-optic and nonlinear optical devices, as well as allowing new kinds of device architectures to be envisioned.

Nonlinear and Electro-Optic Organic Devices

Organic and polymeric materials have emerged in recent years as promising candidates for advanced device and system applications. This interest has arisen from the promise of extraordinary optical, structural, and mechanical properties of certain organic materials, and from the fundamental success of molecular design performed to create new kinds of materials(1). From an optical standpoint, organics offer temporal responses ranging over fifteen orders of magnitude, including large nonresonant electronic nonlinearities (fsec-psec), thermal and motional nonlinearities (nsec-msec), configurational and orientational nonlinearities (μsec-sec), and photochemical nonlinearities (psec-sec). Additionally, organic and polymeric materials can exhibit high optical damage thresholds, broad transparency ranges, and can be polished or formed to high-optical quality surfaces. Structurally, materials can be made as thin or thick films, bulk crystals, or liquid and solid solutions, and can be formed into layered film structures, with molecular engineering providing different optical properties from layer to layer. Mechanically, the materials can be strong and resistant to radiation, shock, and heat. When coupled with low refractive indices and D.C. dielectric constants, the collective properties of these extraordinary materials show great promise towards improving the performance of existing electro-optic and nonlinear optical devices, as well as allowing new kinds of device architectures to be envisioned.

Liquid-Crystal Differentiating Spatial Light Modulator

A nematic liquid-crystal spatial light modulator based on a transverse electro-optic effect is demonstrated. The transverse field is derived from the write light intensity gradient; therefore the device operates in a differentiating or edge enhancing mode. The longitudinal component of the electric field increases the write speed and provides erasure. This drive-off capability is unusual in nematic devices. A bismuth silicon oxide crystal provides photoconductive addressing in a primitive nematic device which demonstrates the effect. Initial experimental results and theory are presented.