Full characterization of a high-power semiconductor disk laser beam with simultaneous capture of optimally sized focus and farfield

Abstract

We report on a beam characterization method that is based on the simultaneous measurement of the focus field and the farfield, thus avoiding problems with beam fluctuations during the measurement. By using reflections from both sides of a planoconvex lens, the method implements two branches of an optical system working simultaneously. Also, by letting the planoconvex lens be antireflection treated, and by allowing for both of the reflected fields to fill large and approximately equal areas on a camera detector array, the method significantly lowers the intensity onto the detector array, thus minimizing the need for additional disturbing attenuation filters to avoid camera saturation. In the numerical retrieval of the phase distribution, based on the measured intensity distributions of the focus and farfield, iterative propagation between the two branches is performed. The phase retrieval uses the two-step algorithm for the numerical field propagation conveniently providing an arbitrary choice of sampling distance in each plane.

1.73 kW CW Amplification ASE Source Based on Yb3+ Ions-Doped All-Fiber System

“…The measuring method adopted the evaluation criteria commonly used in the laser industry [20,21]. We established a nonlinear fitting function for the optical transmission process and used the sampled data to fit the function [22,23]. As shown in Figure 8, the beam quality factor (M 2 ) was 1.649 in the x-direction and 1.763 in the y-direction.…”

Laser mode speckle ghost imaging of underwater environments

“…Siegman introduced the concepts of spatial frequency and intensity moment while establishing a relatively complete theoretical model for the concept of the M 2 factor used to evaluate the laser beam quality [31][32][33] . The M 2 factor has become one of the most widely accepted beam quality parameters for evaluating laser beam quality [34][35][36][37] . The waist radius and the far-field divergence half-angle of the fundamental Gaussian H-G00 laser mode are set as w0 and θ0, and…”

Comparative analysis of numerical methods for the mode analysis of laser beams

“…For the stationary case of stable conditions, the consecutive measurement in both planes with one and the same CCD is an attractive approach to avoiding the need for two cameras. As soon as nonstationary processes occur, however, the limitation to the application of only one CCD requires a more sophisticated setup imaging both planes onto that one CCD simultaneously [28].…”