Studies of Optical Wave Front Conjugation and Imaging Properties of Nematic Liquid Crystal Films

摘要

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 detail 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 images to visible images via real time optical wave mixing processes 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. New optical intensity switching effects and optical beam amplifications and infrared laser wave mixings were also experimentally demonstrated, that will find application in optical switching, image processing and power self limiting devices. (jhd)