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.
© 2012 Optical Society of America
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