Dynamic speckle, reduced extinction, and multiple scattering in holographic optical coherence imaging

Holographic optical coherence imaging (HOCI) records depth-resolved complex fields in a wide-field geometry, making temporal speckle a useful but path-mixed observable. This study presents an operational HOCI framework that links tumor-spheroid fluctuation descriptors to bead-phantom attenuation and residual-reflectivity measurements under defined exposure and sampling conditions. Reduced-extinction and transport-mean-free-path estimates identify when coherence-gated profiles depart from shallow single-scattering behavior. Size-varied bead suspensions show strongest path mixing for nominal 0.50 µm preparations, whereas 0.05 µm suspensions remain closest to the single-scattering limit. The results define practical depth ranges and fitting criteria for interpreting HOCI dynamics in optically dense samples.