Speckleless holographic display by complex modulation based on double-phase method

Abstract

The purpose of this study is to implement speckle reduced three-dimensional (3-D) holographic display by single phase-only spatial light modulator (SLM). The complex amplitude of hologram is transformed to pure phase value based on double-phase method. To suppress noises and higher order diffractions, we introduced a 4-f system with a filter at the frequency plane. A blazing grating is proposed to separate the complex amplitude on the frequency plane. Due to the complex modulation, the speckle noise is reduced. Both computer simulation and optical experiment have been conducted to verify the effectiveness of the method. The results indicate that this method can effectively reduce the speckle in the reconstruction in 3-D holographic display. Furthermore, the method is free of iteration which allows improving the image quality and the calculation speed at the same time.

Holographic display technology based on liquid crystal device

“…By studying the phase modulation properties of SLM and analyzing the error caused by SLM, researchers can optimize the fabrication progress and improve the quality of the reconstructed image further . Moreover, a method to suppress speckle noise in 3D holographic display has been proposed by utilizing a reflective phase‐only SLM based on off‐axis double‐phase complex modulation . As shown in Figure , a blazing grating is proposed to separate the complex amplitude on the frequency plane, and a 4 f system with a filter is used at the frequency plane to suppress noises and higher order diffractions .…”

“…Schematic of optical setup for the multi‐plane holographic display. (This figure has been modified from Qi et al with permission. )…”

“…33 Moreover, a method to suppress speckle noise in 3D holographic display has been proposed by utilizing a reflective phase-only SLM based on off-axis double-phase complex modulation. 34 As shown in Figure 3, a blazing grating is proposed to separate the complex amplitude on the frequency plane, and a 4 f system with a filter is used at the frequency plane to suppress noises and higher order diffractions. 35 The results are recorded by the camera at four different plans with high image quality.…”

P‐99: Method to Reduce Ringing Artifact in Holographic Projection

“…At first, we reduce the distance between the hologram plane and the focal plane and keep the focal length of the convergence light unchanged in random phase-free method. Secondly, the complex amplitude is modulated by using off-axis double-phase method [8]. Consequently, the ringing artifacts and the speckle noise reduction can be achieved with our proposed method.…”

14.2: Reduction of speckle noise by spatial‐multiplexing pixel separation in computer generated holographic display

“…The uncontrolled interference between closely-spaced pixel/object points in the image plane causes the speckle noise due to the initial random phase and the coherent reconstructed light. To solve this problem, many methods are proposed [1,2].…”