Holographic Waveguide Display With Large Field of View and High Light Efficiency Based on Polarized Volume Holographic Grating

• Published in: IEEE photonics journal Vol. 14; no. 1; pp. 1 - 7
• Main Authors: Gu, Yuchen, Weng, Yishi, Wei, Ran, Shen, Zhongwen, Wang, Chuang, Zhang, LiXuan, Zhang, Yuning
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.02.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Augmented reality; Bandwidth; Bandwidths; Brightness; Circular polarization; Diffraction; Diffraction efficiency; Efficiency; Field of view; Holography; Light diffraction; light efficiency; Liquid crystals; Multilayers; Multiplexing; Optical imaging; Optical polarization; Optical reflection; Optical waveguides; Polarized light; polarized volume holographic grating; Rotating liquids; Splicing; Waveguides
• ISSN: 1943-0655; 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2021.3127547

We propose a polarization multiplexing structure based on multilayer reflective polarized volume holographic gratings(PVGs) to improve the field of view and brightness of the augmented reality waveguide display. The multilayer structure forms the splicing of different response bandwidths by stacking PVGs with different periodic components, and realizes the expansion of the wavelength (angle) bandwidth. The polarization multiplexing structure controls the polarization of the diffracted light by controlling the rotation direction of the liquid crystal pitch in the liquid crystal material, so that both left-hand and right-hand circularly polarized light are diffracted to enhance efficiency. Based on these two structures, the wavelength bandwidth of PVG is increased by 40 nm, the angular bandwidth is increased by 10° and the diffraction efficiency is nearly doubled. In order to verify the feasibility of these two structures, we use the holographic waveguide display with OLED as the image source. The demonstrated waveguide prototype shows a complete display with a diagonal field of view of 55°. The brightness of virtual image was measured as high as 1100 cd/m 2 with a transparency of 72% for ambient light.