Study of the modulation characterization of phase-only liquid crystal spatial light modulator by digital holography

The liquid crystal spatial light modulator is becoming a more and more important device due to its wide applications. During its characterization, the phase modulation is the most important one. In this paper, the modulation characterization of a PLUTO phase-only spatial light modulator based on liquid crystal on silicon (LCOS) is studied by applying the lensless Fourier transform digital holography. In the digital holography, the LCOS is used as a reflected sample which modulates the phase of the incident wavefront with respect to the addressed gray level and gives the information of entire active region. This result is then compared with the result obtained by using conventional Michelson Interferometric method and both results are in good accordance with each other. At last the same holographic set up is used for the imaging of phase grating as a reflected object which is addressed to the LCOS and the clear profilometry of the grating is achieved.