Patent ID: 6982790

Claim:
A system for forming an image of an object in a turbid medium, comprising: a laser light source for producing a coherent light beam of a selected frequency; a lens arranged to receive the coherent light beam output from the laser; a beamsplitter arranged to receive the coherent light beam that has passed through the lens and produce a reference beam directed along a reference optical path and a signal beam that is directed along a signal optical path to impinge upon the object in the turbid medium and reflect back toward the beamsplitter; means for modulating the reference beam; a mirror arranged to reflect the reference beam back toward the beamsplitter for combination with the signal beam to produce an output optical signal, the output optical signal having a beat frequency when the signal beam and the modulated reference beam have equal optical path lengths; a photodetector arranged to received the output optical signal from the beamsplitter; and a heterodyne detector connected to the photodetector and arranged to produce a beat signal when the first and second optical paths have matching lengths.