Phase Modulation of Broadband Light Using Liquid-Crystal-on-Silicon Spatial Light Modulator

The influence of the illumination bandwidth on phase modulation using a liquid-crystal-on-silicon (LCOS) spatial light modulator (SLM) was evaluated. The maximum phase modulation for different wavelengths was determined using a Michelson interferometer. Phase modulation of the LCOS SLM exhibited good linearity for broadband light as well as light with a narrow bandwidth. Point spread functions (PSFs) formed via the LCOS SLM were measured for broadband illumination. Although PSF distribution expanded for the broader bandwidth, the full width at half-maximum (FWHM) of the center peak of the PSF remained the same for different bandwidths. Because of the preserved FWHM of the PSF, the resolution of imaging using the LCOS SLM was not influenced by the broadening of illumination bandwidth, but the expanded distribution contributed to the degradation of image contrast. (C) 2011 The Japan Society of Applied Physics