Spatio-angular filter (SAF) imaging device for deep interrogation of scattering media

Optical microscopy is limited to shallow interrogation depths as high-resolution imaging in scattering media is challenging. Current methods require complex and expensive experimental setup or suffer from low resolution. Through gating of photons exiting the scattering media using a restricted numerical aperture (NA) fiber optic plate (FOP), we establish a novel spatio-angular filter imaging device that allows deeper imaging in scattering media. Using dilutions of Intralipid (1-4 v/v%) and a USAF resolution target, it is shown that by reducing the NA of the FOP from 0.55 to 0.17, the interrogation depth improves ~2 times using trans-illumination.