Hybrid Angular Gradient Phase Grating for Measuring the Orbital Angular Momentum of Perfect Optical Vortex Beams

Abstract

We propose an effective method to measure the orbital angular momentum of a perfect optical vortex (POV) beam with a hybrid angular gradient phase grating (HAG-PG), which is a gradient grating with angular changing distribution. The HAG-PG performs the transformation from the POV to the dark stripes of the diffraction intensity patterns. From the number and the orientation of dark stripes of far-field diffraction patterns formed by the HAG-PG, the modulus of TC and sign of the incident POV beam can be determined. The high scalability of this method for being unrestricted by the Fourier plane and its adaptation for measuring the POV beams with different states are demonstrated by loading the HAG-PG hologram on a spatial light modulator. And the detection sensitivity of the POV beam can be significantly improved. The experimental results agree well with the theoretical simulations.

Coherent manipulation of perfect optical vortex via inelastic four-wave mixing in a cold five-level atomic system

“…Different POV beams have been experimentally generated via using different approaches, such as using spatial light modulator [9,10], polymer-based phase plate [11], strongly scattering media [12], single-layer dielectric metasurface [13], etc. In addition, the TC measurement of a POV beam has been realized via exploiting phase shift method [14], optical modal decomposition [15] and hybrid angular gradient phase grating [16]. Quite recently, Dai et al put forward a scheme for the fractional OAM conversion of an asymmetric POV beam by using second-harmonic generation [12].…”

Coherent Control of Perfect Optical Vortex Through Four-Wave Mixing in an Asymmetric Semiconductor Double Quantum Well

“…For instance, different kinds of POV beams have been experimentally generated via using spatial light modulator [28,29], polymer-based phase plate [30], strongly scattering media [31], single-layer dielectric metasurface [32], etc. In situ measurements for TC of POV beams have been realized via exploiting the phase shift method [33], optical modal decomposition [34], and hybrid angular gradient phase grating [35].…”

Phase gradient protection of stored spatially multimode perfect optical vortex beams in a diffused rubidium vapor

“…Considering a more profound perspective for further increasing the information capacity, similar to spatial-mode multiplexing [22], one can nest multiple POVs with independent OAM to form a spatial multimode POV (MPOV) [23], with broad application prospects in high-capacity information processing. To date, research devoted to POVs and MPOVs mainly focuses on generation [24][25][26][27], property analysis [28][29][30][31], optical manipulation [32][33][34] and optical communication [35][36][37][38][39]. A few studies also explore quantum applications and the nonlinear effects based on POVs [40,41].…”