Detection and characterization of an optical inhomogeneity by diffuse photon-pairs density wave in a multiple-scattering medium

摘要

Conventionally, the detection and characterization of an optical inhomogeneity embedded in turbid media is dependent on the perturbation of diffuse photon density wave (DPDW) and its noise level, which is defined as the signal-to-noise ratio (SNR). In this study, we calculate the limitation of detection and characterization by using diffuse photon-pairs density wave (DPPDW) which is a novel method in studying turbid media. DPPDW is produced by linear polarized photon-pairs (LPPPs) laser beam which experience multiple-scattering events in turbid media. Meanwhile, the fractional amplitude and phase noise in detecting heterodyne signal determine the detection and characterization of DPPDW in a multiple scattering medium. The amplitude attenuation and phase change of heterodyne signal of DPPDW and their SNR analysis are demonstrated and discussed. As a result, we anticipate that the properties of DPPDW depending upon the degree of spatial coherence (DOC) and the degree of polarization (DOP) of LPPPs in turbid media can result in an improvement on detection and then the perturbation of DPPDW produced by an inhomogeneity embedded in a multiple scattering medium is able to be measured.