Yang Hongfang, Xue Changxi, Xiao Jing, Chen Jun
Appl Opt. 2020 Nov 20;59(33):10217-10223. doi: 10.1364/AO.403581.
High diffraction efficiency is an important requirement for hybrid diffractive-refractive optical systems with a wide field of view. The issue is that diffractive optical elements cannot maintain high diffraction efficiency across a designed waveband and range of incident angles simultaneously. Glued diffractive optical elements (GDOEs) consist of two single-layer diffractive elements, and optical adhesives are presented to address the problem. Two diffractive optical elements are glued together to reduce the straylight scattered into unwanted diffraction orders. The parameters of diffractive optical elements are optimized to achieve broadband high diffraction efficiency and modulation transfer function over a wide-incident-angle range. The GDOEs enable the system to realize a diffraction efficiency of over 90% when the incident angle is no more than 58°. Through gluing two single-layer diffractive optical elements together, we can minimize the inner reflection and refraction. Diffraction efficiency losses can be compensated by the optical adhesives layer, and image quality can be improved. Our design method could make possible the use of diffraction elements in different kinds of optical systems.
高衍射效率是宽视场混合衍射-折射光学系统的一项重要要求。问题在于，衍射光学元件无法在设计的波段和入射角范围内同时保持高衍射效率。胶合衍射光学元件（GDOEs）由两个单层衍射元件组成，并引入光学粘合剂来解决该问题。将两个衍射光学元件胶合在一起，以减少散射到不需要的衍射级中的杂散光。对衍射光学元件的参数进行优化，以在宽入射角范围内实现宽带高衍射效率和调制传递函数。当入射角不超过58°时，GDOEs可使系统实现超过90%的衍射效率。通过将两个单层衍射光学元件胶合在一起，可以将内部反射和折射降至最低。衍射效率损失可由光学粘合剂层补偿，从而提高图像质量。我们的设计方法能够使衍射元件在不同类型的光学系统中得到应用。
