Determination of the beam centroid of an obstructed focused Gaussian laser beam.
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.
St John
W Doyle
WD
Department of Chemistry and Engineering Physics, University of Wisconsin-Platteville, Platteville, Wisconsin 53818, USA. stjohn@uwplatt.edu