Research for Free-Space Optical Beam Control with Liquid Crystal

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The liquid crystal is considered as simple and efficient devices in the field of optical interconnects and optical computing. In the present research, we investigated the design and fabrication for free-space optical beam control device with liquid crystal in realtime. The main results throughout these two years' research since the Heisei 7th academic year, are presented below.1) Fabrication and characteristic estimation of array type liquid crystal optical beam device :We developed a homogeneous nematic liquid crystal panel using electrodes with distributed resistivity for the purpose of continuously modulating the wavefront either by a linear or quadratic function. The experimetal results show excellent congruity with the theoretical calculations. Furthemore, we designed and fabricated both spatial phase modulator unit cell and cell array incorporating electrodes with distributed resistivity.2) Efficient array illuminator for liquid crystal optical beam device :Based on the Talbot ef … More fect, we designed and fabricated a new type of array illuminators consisting of a multilevel phase grating crystal beam device with large subapertures, Details of the phase grating and the improved optical throughput are obtained.3) Desin and fabrication of two-dimentional illuminator :The extension to a two-dimensional illuminator is straightforward. By implementing on one plate a two-dimensional phase profile which consists of the phase sum of two one-dimensional Talbot plates but superimposed orthogonally, we can obtain intensity patterns for various SLM devices aperture ratios.4) Theoretical and experimental evaluation of waveguide array illuminators :We successfully confimed the theoretical results in an experiment demonstrating the existence of the high-contrast intensity distributions up to the edge of the waveguide. We concluded that waveguide array illuminators are expected to be useful for optical interconnects.5) Examination of two-dimentional liquid crystal optical beam devices :We obtained the concept of novel two-dimentional liquid crystal devices for efficient wavefront modulation with low electric power and high speed. Less