Nonmechanical Laser Beam Steering Based on Polymer Polarization Gratings: Design Optimization and Demonstration
Journal of Lightwave Technology, 33(10), (2015). https://doi.org/10.1109/JLT.2015.2392694
We present a wide-angle, nonmechanical laser beam steerer based on polymer polarization gratings with an optimal design approach for maximizing field-of-regard (FOR). The steering design offers exponential scaling of the number of steering angles, called suprabinary steering. The design approach can be easily adapted for any 1-D or 2-D (e.g, symmetric or asymmetric FOR) beam steering. We simulate a system using a finite difference and ray tracing tools and fabricate coarse beam steerer with 65° FOR with ~8° resolution at 1550 nm. We demonstrate high optical throughput (84%-87%) that can be substantially improved by optimizing substrates and electrode materials. This beam steerer can achieve very low sidelobes and supports comparatively large beam diameters paired with a very thin assembly and low beam walk-off. We also demonstrate using a certain type of LC variable retarder that the total switching time from any steering angle to another can be 1.7 ms or better.