An analytical expression for the diffraction of an elliptic Laguerre-Gaussian (LG) beam is derived and analyzed. We show that a beam with even singularity order has nonzero axial intensity for any degree of ellipticity and at any finite distance z from the initial plane, whereas at z=0 and z=∞ the axial intensity is zero. We show that for a beam with a small degree of ellipticity and even order of singularity, two isolated intensity zeroes appear in the Fresnel zone on a straight line at an angle of 45 deg or −45 deg, depending whether the beam's spin is right or left. The theoretical conclusions are confirmed by numerical simulation and physical experiments.
© 2006 Optical Society of America
Diffraction and Gratings
Victor V. Kotlyar, Svetlana N. Khonina, Anton A. Almazov, Victor A. Soifer, Konstantins Jefimovs, and Jari Turunen, "Elliptic Laguerre-Gaussian beams," J. Opt. Soc. Am. A 23, 43-56 (2006)