Systems and methods for imaging ear tissue include: directing illumination radiation to pass through an intact biological structure and be incident on ear tissue that does not include an exogenous fluorophore, at a plurality of locations, the illumination radiation including a plurality of light pulses each having a temporal duration of 500 femtoseconds or less for each one of the plurality of locations, using a detector to detect radiation emitted from the location that passes through the intact biological structure and forming an image of the tissue based on the detected radiation at each of the plurality of locations, where the emitted radiation corresponds to endogenous two-photon fluorescence of the tissue.