Vortex volume gratings with high diffraction efficiency at 1064 nm

Vortex volume grating (VVG) has advantages of high diffraction efficiency (DE), excellent angular selectivity, broad spectral band, and flexible design, making it a good candidate as an orbital angular momentum (OAM) generator in high power laser system.. In our research, a vortex volume grating with a relative diffraction efficiency of 84.58% and an angular spectrum of 1.864 mrad at 1064 nm is fabricated, and the refractive index modulation (RIM) is retrieved.