Variable coherence in determining the scattering parameters of diffuse media using laser speckle

Summary form only given. We demonstrate the application of a variable-coherence laser source for determining the scattering parameters of a diffuse medium and the potential for imaging spatially-dependent scatter. A key concept in this work in the ability to synthesize a variable-coherence source by frequency modulating a tunable laser diode (with a center wavelength of 850 nm) at a rate much faster than the integration time of the detector. This allows for a rapid measurement and the adaption of laser coherence to the degree of scatter, which we show is critical in obtaining the necessary sensitivity.