A ferroelectric liquid crystal spatial light modulator encoded with orthogonal arrays and its optimized design for laser speckle reduction

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• 作者：Zhaomin Tong^a ; ^b ; ^{zhaomin.tong@sxu.edu.cn} ; Xuyuan Chen^a ; ^b ; ^c
• 关键词：Laser projectors ; Speckle reduction ; Binary phase diffuser ; Two-level orthogonal array ; Spatial light modulator ; Passive matrix addressing
• 刊名：Optics and Lasers in Engineering
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：90
• 期：Complete
• 页码：173-178
• 全文大小：1106 K
• 卷排序：90

文摘

Speckle is the bottleneck problem in laser displays. Speckle reduction can be achieved by fast vibrating random phase diffusers (RPDs) during the detector integration time. Binary phase diffusers (BPDs) generated from two-level orthogonal arrays were firstly proposed by our group (App. Optics 49(33), 6425-6429 (2010)). BPDs are the optimization over RPDs, where the number of phase patterns realization step can be greatly reduced. In this paper, we demonstrate the feasibility of using the ferroelectric liquid crystal spatial light modulator (FLC-SLM) programmed by orthogonal arrays to reduce laser speckle. The FLC-SLM works under “0” and “255” grayscales to generate the “0” and “π” radian phase modulation depths, respectively. The speckle contrast ratio is reduced from Cb = 0.71 before to Ca = 0.1 after driving the FLC-SLM. We suggest a transparent FLC-SLM with a passive matrix addressing scheme. The proposed FLC-SLM can be driven electronically with reduced number of controlling electrodes, and only two grayscales are needed. Therefore, it is a great optimization over our currently used FLC-SLM. The proposed FLC-SLM has a higher fill factor compared to our previously reported binary micromirror array (Sensor. Actuat. A-Phys. 210, 209–216 (2014).