Opt Lett. 2018 Dec 1;43(23):5773-5776. doi: 10.1364/OL.43.005773.
In this Letter, we demonstrate polarization volume grating (PVG)-based couplers for a double-layer waveguide display to realize a full-color near-eye display. The polarized interference exposure with photo-alignment methods was employed to generate a birefringent spiral configuration with two-dimensional periodicity in a chiral-dopant reactive mesogen material. Such a structure presents a unique highly efficient single-order Bragg diffraction with polarized selectivity. The prepared PVG couplers exhibited over 80% diffraction efficiency with large diffraction angles at spectra of blue (457 nm), green (532 nm), and red (630 nm). The demonstrated waveguide prototype showed a full-color display with a diagonal field of view of around 35°. The overall optical efficiency was measured as high as 118.3 cd/m per lumen with a transparency of 72% for ambient light.
在这封信件中，我们展示了基于偏振体光栅 (PVG) 的双层波导显示器耦合器，以实现全彩近眼显示器。采用偏振干涉曝光和光取向方法在手性掺杂向列相介晶材料中生成具有二维周期性的双折射螺旋结构。这种结构呈现出独特的高效单阶布拉格衍射，具有偏振选择性。所制备的 PVG 耦合器在蓝色 (457nm)、绿色 (532nm) 和红色 (630nm) 光谱下具有超过 80%的衍射效率和大的衍射角。所展示的波导原型显示出全彩色显示，视角约为 35°。整体光学效率高达每流明 118.3 cd/m，环境光透过率为 72%。
