Quantifying the paraxiality for laser beams from the M2 factor

Opt Lett. 2009 Feb 1;34(3):340-2. doi: 10.1364/ol.34.000340.

Abstract

A useful relationship among the parameter called paraxial estimator [Opt. Lett. 32, 927 (2007)] and two parameters concerning the beam quality, the M2 factor, and the beam spot size was derived. This relationship allows one to quantify the paraxiality for a monochromatic laser beam from standard measurements extending the applicability of such an estimator for real beams even if the beam profile shape does not have a closed-form representation. Hence, the paraxial estimator might be a suitable tool for deepening the analysis on the quality of a laser beam.