Optimization of a phase-only spatial light modulator for the improvement of Bessel beam generation
Abstract
A Bessel beam generation method using an optical setup with a spatial light modulator encoded with a conical phase is presented. Phase modulation analysis of the SLM shows that mapping of the input conical phase, having 0 to 2π phase values represented as 8-bit gray levels, into the actual values interpreted by the SLM adds errors in the beam produced. The SLM was calibrated using a Michelson interferometer to determine the phase shifts introduced by the gray values. Rescaling the holograms according to the approporiate gray values allowed the optimization of the beams produced. The pixel crosstalk in the SLM was also observed. It was shown that the characteristic point spread function of the SLM which causes spatial low pass filtering of the hologram, is a sinc function.