Optimization of forward-scattered light energy and de-coherence of Mie scattering for speckle suppression

• DOI: 10.1007/s11082-014-9907-1
• Publication Date: 2014-03-10T19:21:00Z
• Authors: Yanhong Wang; Pengfei Zhao; Wenhong Gao; Xuyuan Chen
• Keywords: 01 natural sciences; 0104 chemical sciences

Reducing the coherence of laser light without energy loss is critical for speckle suppression in laser projectors. In this paper, it is shown that more than 90 % of incident light is forward-scattered with complete de-coherence. We modeled a scattering volume with particles in ZEMAX as a scattering medium and studied the forward-scattered light energy and de-coherence dependence on the following three parameters: particle concentration, normalized radius of particles $$\upalpha $$ and refractive index ratio m. By varying all three parameters, a number of parameter combinations to achieve complete de-coherence are obtained, and which are utilized for speckle suppression. The forward-scattered light energy loss is up to 60–70 % of incident light at these combinations. But, at smaller particle concentration, the loss drops quickly. When setting the particle concentration at $$1\times 10^{8}\,\hbox {cm}^{-3}$$ , the forward-scattered light energy can be more than 90 % of incident light by adjusting $$\upalpha $$ and m according to Mie scattering theory. The structure parameter L of the scattering volume is also analyzed to collect forward-scattered light more than 90 % of incident light. These results can benefit the parameters’ choice of scattering particles and the design of a scattering volume used for speckle suppression.