Identification of the laser-beam field in the emission and measurement planes
摘要
We consider an important practical problem of identification of the laser-beam field in the planes of location of the emitter (emitter plane) and measuring instrument (measurement plane). The solution of this problem allows us to get additional information about the parameters of the laser beam required for manufacturing and certification of laser sources. As the only existing standardized numerical characteristic, we can mention the measure M2 (GOST R ISO 11146-1-2008 “Lasers and laser installations (systems). Methods for measuring widths, divergence angles, and propagation coefficients of laser beams”), which determines the quality of a laser beam and enables to estimate the degree of similarity of the measured spatial distribution of the beam intensity solely with the spatial distribution of the Gaussian intensity in the measurement plane. We have developed an alternative measure of similarity of the measured spatial distribution of the laser-beam amplitude with a uniform distribution of amplitude in the emitter plane or a spatial distribution of the intensity of laser beam with an arbitrarily given distribution in the measurement plane. It is shown that the alternative measure of similarity located in the emitter plane coincides with the aberration factor specifying the source with the greatest axial luminous intensity. The proposed measure is universal and has broader applications than the measure M2 because it is associated with the characteristic of homogeneity of the field distribution, the generalized area, and the generalized diameter of the laser beam, which is an alternative to the beam diameter determined according to GOST R ISO 11146-1-2008.