Design and experimental demonstration on improved high order grating for wide angle beam steering of liquid crystal optical phased array

To realize a non-mechanical laser beam deflector with a wide steering range, improved high order grating method (i-HOG) was theoretically proposed on the promising optical phased array device using the material of liquid crystal. In this paper, experimental prototype and results are presented to verify the performance on the wider steering range when the method of i-HOG was applied on the corresponding device. To satisfy the requirement on much deeper phase retardation, the optical film of liquid crystal was redesigned and fabricated as well as driving hardware. Comparing with the conventional methods where the modulo of phase delay is 2 pi, liquid crystal optical phased array using the method of i-HOG can succeed a double steering range. Meanwhile, experimental results also show better diffraction efficiency.