Optimization of Optical Phase Profile in Beam Deflector based on NLCs with Advanced Simulation Method for High Diffraction Efficiency
Controlling the phase of light with high efficiency and precision is essential for applications in imaging, tunable devices and optical systems. Spatial light modulators (SLM) based on liquid crystals (LCs) have always been among the best choices for the generation of phase profiles for steering the light. The upper glass substrate has an unpatterned electrode for a common electrode, while the lower glass substrate has the one-dimensional micro-patterned electrodes for controlling the single pixel level by the applied voltages. By applying different voltages to each electrode to create a sawtooth-shaped phase profile, the collimated input beam is deflected to the desired angle. To maximize the diffraction efficiency (DE) values, the advanced simulation method has been developed to find the optimized phase profile through the analysis of the LC director distribution. Experimental result of DE shows a high correlation with the theoretical model from the advanced simulation method. Finally, the beam deflector (BD) system with advanced driving algorithm has a high 1st order DE, about 60％, 32％ and 7.5％ at 1°, and 3° and the maximum steering angle of 7.5°, respectively. The optimization of optical phase profile in BD with the advanced simulation method can be widely used for many types of beam steering devices using LC with advantages of finding the most efficient driving algorithm.
- Micromachines 13, no. 5: 802.