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.
© 2011 Optical Society of America
Lasers and Laser Optics
Original Manuscript: November 11, 2010
Revised Manuscript: January 28, 2011
Manuscript Accepted: February 4, 2011
Published: April 11, 2011
Carl Borgentun, Jörgen Bengtsson, and Anders Larsson, "Full characterization of a high-power semiconductor disk laser beam with simultaneous capture of optimally sized focus and farfield," Appl. Opt. 50, 1640-1649 (2011)