Glued diffraction optical elements with broadband and a large field of view.

Abstract

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.