Arbitrary Beam Steering Enabled by Photomechanically Bendable Cholesteric Liquid Crystal Polymers

Beam‐steering technology is now in widespread use in a variety of optical systems, spanning from fiber‐optic interconnector to Lidar. Most current techniques are based on optical grating diffractions; they are thus subject to not only finite tuning range, direction, and efficiency but also complex inorganic fabrication and circuit design. A high‐degree‐of‐freedom beam‐steering element makes such operations more efficient and versatile. Azobenzene cholesteric liquid crystal polymer (azo‐ChLCP) can be regarded as a soft self‐assembled Bragg mirror capable of being bent photomechanically. With proper control of pump polarization and exposure time, the output beam can be directly steered to an arbitrary direction. The deflection efficiency was achieved to be at least 90% with an angular tuning range of ≈54°, which is markedly superior to conventional grating‐based devices. Additionally, the angle of deflection is independent of wavelength, preventing the deflected beam from spreading out with colors. This work demonstrates and characterizes the azo‐ChLCP beam deflector, which features optical tunability, high efficiency, wide tuning range, and polarization‐selective deflection direction, making a significant breakthrough in beam‐steering technology. All‐optical 3D beam steering is enabled by a thin film of cholesteric azobenzene liquid crystal polymer. Such a beam steerer features polarization‐selective deflection direction, wide tuning range, high efficiency (>90%), and broad operation spectrum.