Yan Xudong, Wang Jiawei, Zhang Wei, Liu Yanjun, Luo Dan
Opt Express. 2023 Oct 9;31(21):35282-35292. doi: 10.1364/OE.503493.
Angular bandwidth, which is critical to field-of-view, plays important role in diffractive optical waveguide augmented reality display. However, design and fabrication of large angular bandwidth is still a challenge. Herein, we demonstrate a liquid crystal reflective gradient polarization volume grating with three-dimensional gradient periodic structure for waveguide near-eye display. Two-beam polarization interference with special designed periodic gradient photomask are applied to chiral-dopant reactive mesogens doped with ultraviolet dye for generating gradient three-dimensional configuration of liquid crystals, resulting in gradient polarization volume grating with extended angle bandwidth of 61° while keeping 80% diffraction efficiency, with peak efficiency near 100%. The proposed gradient polarization volume grating provides an effective method to broaden the angular bandwidth in waveguide for wide field-of-view augmented reality display.
角带宽对于视场至关重要，在衍射光波导增强现实显示器中起着重要作用。然而，大角带宽的设计和制造仍然是一个挑战。在此，我们展示了一种用于波导近眼显示的具有三维梯度周期结构的液晶反射梯度偏振体光栅。采用具有特殊设计的周期梯度光掩模的双光束偏振干涉，作用于掺杂有紫外染料的手性掺杂反应性液晶，以产生液晶的梯度三维构型，从而得到角带宽扩展至61°且衍射效率保持在80%、峰值效率接近100%的梯度偏振体光栅。所提出的梯度偏振体光栅为拓宽光波导中的角带宽以实现宽视场增强现实显示提供了一种有效方法。
