Diffraction of an obstructed focused Gaussian laser beam has been treated theoretically using the Huygens–Fresnel diffraction integral and was found to be in good agreement with experimental measurements. The obstruction is a vertically oriented opaque cylinder treated as a flat hard aperture. Measurements and calculations are compared for the diffracted irradiance profile and the beam centroid as a function of cylinder diameter and lateral and longitudinal placement along the optic axis. The cylinders used were gauge pins and/or wires with diameters from 0.5 to 100 mil.
© 2009 Optical Society of America
Instrumentation, Measurement, and Metrology
Original Manuscript: May 14, 2009
Revised Manuscript: July 9, 2009
Manuscript Accepted: July 14, 2009
Published: July 29, 2009
W. Doyle St. John, "Determination of the beam centroid of an obstructed focused Gaussian laser beam," Appl. Opt. 48, 4501-4505 (2009)