HoloChrome: Polychromatic Illumination for Speckle Reduction in Holographic Near-Eye Displays

TL;DR

HoloChrome introduces a polychromatic holographic display framework using wavelength multiplexing and dual-SLMs to significantly reduce speckle noise and expand color gamut in near-eye holographic displays.

Contribution

The paper presents a novel polychromatic holographic display architecture with dual-SLMs and wavelength multiplexing for effective speckle reduction and enhanced color reproduction.

Findings

Significant speckle noise reduction demonstrated in simulations and experiments.

Expanded color gamut compared to traditional holographic displays.

Effective integration of ultrafast, wavelength-adjustable laser with dual-SLM setup.

Abstract

Holographic displays hold the promise of providing authentic depth cues, resulting in enhanced immersive visual experiences for near-eye applications. However, current holographic displays are hindered by speckle noise, which limits accurate reproduction of color and texture in displayed images. We present HoloChrome, a polychromatic holographic display framework designed to mitigate these limitations. HoloChrome utilizes an ultrafast, wavelength-adjustable laser and a dual-Spatial Light Modulator (SLM) architecture, enabling the multiplexing of a large set of discrete wavelengths across the visible spectrum. By leveraging spatial separation in our dual-SLM setup, we independently manipulate speckle patterns across multiple wavelengths. This novel approach effectively reduces speckle noise through incoherent averaging achieved by wavelength multiplexing. Our method is complementary to existing speckle reduction techniques, offering a new pathway to address this challenge. Furthermore, the use of polychromatic illumination broadens the achievable color gamut compared to traditional three-color primary holographic displays. Our simulations and tabletop experiments validate that HoloChrome significantly reduces speckle noise and expands the color gamut. These advancements enhance the performance of holographic near-eye displays, moving us closer to practical, immersive next-generation visual experiences.