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 AmericaFull Article | PDF Article