Simple and robust approach to uniform laser beam splitting with a spatial light modulator

A simple and robust approach to laser beam splitting employing a spatial light modulator is presented. A weighted, one-dimensional Gerchberg-Saxton algorithm with a target intensity distribution consisting of separated pixels is employed. The resulting phase is a Fourier series and thus a strictly periodical grating. The orthogonal superposition of these gratings enables two-dimensional beam arrays with high uniformity. The approach is not prone to numerical artifacts generating speckles. Due to the strict periodic nature of the grating, the split beam uniformity is hardly affected by misalignment, beam quality, or high laser input power. The diffraction efficiency is high.