Liquid Crystal Based Optical Phased Array for Steering Lasers

摘要

Beam steering technologies are attracting more and more research interests and attention because of the benefits of fast tuning, light weight, and synergy with adaptive optics. The liquid crystal OPA technology has been considered for small angle beam steering because of the small pitch, low driving voltages, large birefringence, flexibility, and electrical control. However, the large area resets of the phase profile caused by the fringe fields degrade the achievable device efficiency. Decentered micro-Lens Arrays (DLAs) are excellent as a candidate for moderate angle beam steering, but have mechanical deficiencies. When the micro-lens arrays are transformed and encoded into liquid crystal devices, we can replace the mechanical motion of lenslet with electrical control of the voltage profile precisely. In this work, we develop a liquid crystal tunable polarization grating device characterized with continuous angular tuning capability and high efficiency.