Polarization-Resolved Digital Holographic Sensing for Simultaneous Morphological and Polarimetric Characterization of Microparticles

Multiparameter optical sensing of micrometer-sized particles requires morphological and optical responses to be resolved for the same particles. We present a polarization-resolved digital holographic (PRDH) system combining digital in-line holography with division-of-focal-plane polarimetry. Numerical refocusing associates the three-dimensional location of each resolved particle with its equivalent diameter, major and minor axes, perimeter, projected area, and shape factor, together with the linear Stokes parameters S0, S1, and S2 and the degree of linear polarization (DoLP). For three standard glass-microsphere groups, the average absolute relative deviation between group-mean measured diameters and the nominal reference values was approximately 5.5%. The 5 and 10 micrometer borosilicate groups had mean DoLP values of 0.849 and 0.843, respectively, while other sample groups exhibited different responses. An exploratory regression against the adopted nominal refractive-index values is reported as a conditional group-level description, not as a refractive-index calibration. T-matrix calculations at 520 nm illustrate angular variations with size and refractive index without quantitatively reproducing the complete holographic measurement. Ice-cloud-chamber measurements further demonstrate the application of the particle-resolved analysis. PRDH thus provides associated positional, projected morphological, and linear-polarization information within a three-dimensional particle field.