A new and simple method for measuring the spot size of a laser beam is presented. In this method, the spot of a laser beam is scanned transversely across a straight boundary, and the intensity profile of the boundary-diffraction wave is observed. This intensity profile makes it possible to measure the spot size. The spot size of a He–Ne laser beam (wavelength 633 nm) has been measured to be 8.3 μm by using a Si3N4 straight pattern; this value is compared with 8.9 μm obtained by the knife-edge method.
© 1987 Optical Society of America
Original Manuscript: February 17, 1987
Manuscript Accepted: May 21, 1987
Published: August 1, 1987
S. Kimura and C. Munakata, "Method for measuring the spot size of a laser beam using a boundary-diffraction wave," Opt. Lett. 12, 552-554 (1987)