Design and Fabrication of Volume Holographic Gratings with Large Angular Bandwidth and High Diffraction Efficiency

High-performance volume holographic grating (VHG) is an important coupling element for a holographic waveguide system. Small angular bandwidth and low diffraction efficiency restrict the applications of VHGs. Based on asymmetrical recording, a reflection VHG with large angular bandwidth and high diffraction efficiency are designed and prepared. The relationship between the recording angles and the diffraction efficiency is discussed first and several combinations of the recording angles are found. Then the relationship between the recording angles and the angular bandwidth is further analyzed, which could obtain the optimal recording setup. The experimental results show that when the incident angle of the reference light and signal light is 10° and 59°, the angular bandwidth of the fabricated VHG reaches 25° and the diffraction efficiency is 90%. However, the wavelength shift happens. The recording angle is modified to improve wavelength shift. The method proposed in this paper could help design a VHG with large angular bandwidth and high diffraction efficiency.