Abstract

The beam radius is measured exploiting the relationship between the beam diameter and power transmitted through the grating. Gratings of various functional characteristics, such as rectangular, periodic,¹ and aperiodic² grating, have been used for laser beam diameter measurement. However, the calibration curve relating the beam radius to the minimum to maximum power ratio is nonlinear in nature. In this work, we propose to design a novel periodic grating so that the relationship is linear. Numerical least-squares technique coupled with generalized Fourier series is applied to fit the characteristics curve to a straight line. Depending on the choice of Fourier coefficients several designs are shown. Gratings of such characteristics can be fabricated by the contact screen method. We believe this to be the first known grating designed with this approach.

© 1991 Optical Society of America