Experimental generation of a kind of reversal rotating beams

Opt Express. 2020 Feb 3;28(3):2884-2894. doi: 10.1364/OE.385188.

Abstract

A kind of reversal rotating beams with astigmatic phase is proposed, whose spectral density and degree of coherence both follow anisotropic Gaussian distribution. Unlike a general rotating beam, the spectral density and the degree of coherence of this beam can be reversal rotated during propagation, that is, the direction of rotation could change automatically. Such a beam can be viewed as having two elements with astigmatic phase and partial coherence of the beam, which can reshape the cross-spectral density, corresponding to two directions of rotation. We generated this beam successfully in experiment and observed the expected phenomenon, which is basically consistent with the result of the numerical simulation. The reversal rotating beam has certain requirements on the astigmatic phase, which is analyzed and verified. The effect of the main parameters in astigmatic phase on the reversal rotation is further studied from both simulation and experiment.