Nonsequential Speckle Reduction Method by Generating Uncorrelated Laser Subbeams with Equivalent Intensity Using a Reflective Spatial Light Modulator

Abstract

Sequential speckle reduction methods demand the usage of fast modulators due to the short integration period of human eyes. Here, a nonsequential speckle reduction method by splitting one laser beam with short coherence length into uncorrelated laser subbeams(LSBs)isreported.Inordertorealizethemostefficientspecklereduction,withthe help of a polarization beam splitter, we have programmed a reflective spatial light modulator to make the LSBs intensities equivalent. Three uncorrelated LSBs with equivalent light intensity are designed to demonstrate this idea; the speckle contrast ratio is reduced to 0.55, which closes to the expected value of 0.58. This nonsequential speckle reduction method has no requirement of the modulators speed; thus, it has obvious merit comparing with the sequential speckle reduction methods.