Holographic amplification of the diffraction angle from optical phase array for optical beam steering

摘要

Beam steering in lidar applications presents an important engineering problem, as researchers seek to achieve the highest possible field of view with low energy cost and rapid refresh rate. Non-mechanical beam-steering technologies that exist today are known to achieve a low energy cost and rapid refresh rate, but they have a narrow angular range. A method by which the diffraction angle from a beam-steering device may be increased to cover a 4 pi sr solid angle is presented. Multiple holograms are recorded in the same volume hologram in a process called multiplexing. This multiplexed hologram can diffract light over a solid angle of 2 pi sr. To increase the angular coverage up to 4 pi sr, a hemispheric lens is attached to the volume hologram. Secondary holographic optical elements coated on the lens surface further diffract the light, directing it to a theoretical maximum of 4 pi sr. An early prototype demonstrates five distinct diffraction angles, ranging from 20 degrees to 150 degrees, which covers a solid angle around 90% of the entire sphere while maintaining beam collimation. (C) 2019 Optical Society of America