Photosensitive Liquid Crystals: Next Generation Materials for Dynamic Holography and Electro-Optics

摘要

Report developed under SBIR contract for topic AF99-162. The objective of this work was to prove the feasibility of highly nonlinear, photosensitive, Liquid Crystalline (LC) materials that a) possess photosensitivity comparable to that of photoconductive semiconductors used in LC spatial light modulator, and b) allow extremely strong modulation of the refractive index (modulation of birefringence). Such unique combination of photosensitivity and large optically induced index modulation property of LC would make these materials the prime candidate for a new generation of high performance dynamic holography devices, optical limiters, spatial light modulators (SLM) and other signal/image processing and optically or electronically tunable diffractive devices. These materials will trigger new markets due to drastically reduced cost for intelligent optical systems. The goals of the project were achieved by 1) developing NLC-systems with enhanced optical nonlinearity in blue/green, red and infrared region of wavelengths; 2) study into the mechanisms of photoexcitation-induced enhancement of optical nonlinearity; and successful demonstrations of 3) new principles of spatial light modulation; 4) wave transformation with efficiency over 90%; 5) image conversion between incoherent beams with the aid of NLC; and 6) optical limiting with dynamic range greater 3000.