Four-phase holography for high-quality light field modulation with MEMS phase light modulators

Many advancements in the fields of holographic displays, image projection, and structured illumination rely on phase-only spatial light modulators (SLMs) to generate light fields with high dynamic range and little light loss. However, commonly used Liquid Crystal on Silicon (LCoS) SLMs are typically slow (5 kHz) holographic illumination and display technologies. However, their bit depth is still limited to four-to-five bits, causing many light field modulation and optimization methods, such as Gerchberg-Saxton phase retrieval, to produce poor-quality results. In this contribution, we introduce an iterative modulation algorithm which combines a four-phase PLM level averaging method with Gerchberg-Saxton phase retrieval to enable complex field modulation while simultaneously improving the bit depth of the modulator, the PSNR of projected images, and contrast of projected images.