Angular diffraction of an optical vortex induced by the Gouy phase

• Published in: Journal of optics (2010) Vol. 14; no. 5; pp. 55707 - 1-7
• Main Authors: Cui, H X, Wang, X L, Gu, B, Li, Y N, Chen, J, Wang, H T
• Format: Journal Article
• Language: English
• Published: Philadelphia, Pa IOP Publishing 01.05.2012; IOP
• Subjects: Algorithms; Angular momentum; Angular position; Diffraction; Diffraction and scattering; Diffraction patterns; Emergence; Exact sciences and technology; Fluid flow; Fundamental areas of phenomenology (including applications); Gouy phase; optical angular momentum; optical diffraction; Optics; Physics; Vortices; Wave optics; optical angular momentum; Uncertainty principle; Electromagnetic wave diffraction; Digital simulation; Angular momentum; Gouy phase; Fast algorithm; optical diffraction; Optical vortex
• ISSN: 2040-8978; 2040-8986
• DOI: 10.1088/2040-8978/14/5/055707

We investigate the diffraction of an optical vortex, when half of the beam is blocked by a knife edge. The Gouy phase is shown to influence the diffraction pattern strongly, in particular leading to the emergence of distorted and deformed diffraction fringes in the azimuthal direction. In analogy with single-slit diffraction, this phenomenon is analyzed in terms of angular diffraction within the azimuthal degree of freedom, by considering the uncertainty principle for the angular position and the angular momentum. Numerical simulations based on the fast-Fourier algorithm and the angular momentum expansion fit well with the experimental results.