Electrically controlled Kerr effect in magnetophotonic crystals based on nematic liquid crystals J. Appl. Phys.The encapsulation of liquid crystals in a polymer matrix produces a material with interesting and potentially useful optical properties. The earliest efforts generated a dispersed phase whose dimensions were comparable to optical wavelengths and therefore afforded materials which were highly scattering. These materials have already been found useful for display applications. We have found that when these materials are fabricated so that the dimensions of the dispersed phase are substantially smaller than the incident radiation wavelengths, the material is far less scattering. de Kerr measurements on these liquid-crystal composites yield quite large values, ranging as high as 30000 times CS 2 This activity is shown to be a strong function of the liquidcrystal loading and the temperature. 4253 J.

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for photons radiated at 90'. The primary results of this work provide a test of the photon-energy dependence of the doubly differential cross section to an accuracy of 3%. Results for the absolute cross section with an accuracy of 22%%uo are also presented.

Solid state optical gain media based upon organic dyes are an attractive alternative to solvent based systems, however the poor thermal and photo-stability of these dyes in polymer hosts has limited their use to date. Organically modified silicates (ORMOSIL's) may offer a partial solution by providing a host matrix with superior qualities. Examples of some of these qualities are excellent optical clarity, low-temperature synthesis, high laser damage threshold, good mechanical strength, and excellent host/dye compatibility. We will report on progress at Lockheed and UCLA on the development of these materials for use as solid-state tunable lasers and amplifiers. Lasing and gain characteristics of common laser dyes (Rhodamine 6G and B) in terms of their optical conversion efficiency and lifetime will be discussed. Efficiencies as high as 39% and output energies >10 mJ have been achieved from laserpumped plate and rod ORMOSIL laser cavities.