Suppression of the zero-order diffracted beam from a pixelated spatial light modulator by phase compression.
Phase compression is used to suppress the on-axis zero-order diffracted (ZOD) beam from a pixelated phase-only spatial light modulator (SLM) by a simple modification to the computer generated hologram (CGH) loaded onto the SLM. After CGH design, the phase of each SLM element is identically compressed by multiplying by a constant scale factor and rotated on the complex unit-circle to produce a cancellation beam that destructively interferes with the ZOD beam. Experiments achieved a factor of 3 reduction of the ZOD beam using two different liquid-crystal SLMs. Numerical simulation analyzed the reconstructed image quality and diffraction efficiency versus degree of phase compression and showed that phase compression resulted in little image degradation or power loss.
Electrical and Computer Engineering Department, University of Texas at Austin, Austin, Texas 78712, USA. jinyang.liang@mail.utexas.edu
Jinyang
J
Liang
Sih-Ying
SY
Wu
Fredrik K
FK
Fatemi
Michael F
MF
Becker