Studies of Optical Wave Front Conjugation and Imaging Properties of Nematic Liquid Crystal Films.
Annual rept. 15 Sep 84-14 Sep 85,
PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF ELECTRICAL ENGINEERING
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Optical nonlinearities of liquid crystals owing to laser induced molecular reorientation or laser induced thermal index change, were studied in the context of optical wave mixings and real time imagings. The basic mechanisms and the dynamics of the nonlinearities were studied in details in theories, and in experiments using lasers of various time scales and temporal characteristics. Quantitative documentation of nanosecond laser induced thermal grating was performed for the first time, and further established the optical imaging and switching capabilities of nematic liquid crystal film. The conversion of infra-red images to visible images via real time optical wave mixing process was also demonstrated. The capability of optical four wave mixing to generate amplified reflection and self oscillation in nematic liquid crystal film was also demonstrated for the first time. Such a process will be useful for image processing as well as laser oscillator adaptive optics applications. In this period, new optical intensity switching effects using the transverse optical nonlinearity were also experimentally demonstrated, that will find applications in optical switching and power self limiting devices.