Patent ID: 7973939

Claim:
A differential-phase polarization-sensitive optical coherence tomography (DP-PSOCT) system for measuring a specimen, comprising: a polarized heterodyne interferometer including a light source module operable to generate a circularly polarized output beam, a beam splitter for splitting the circularly polarized output beam into a circular polarized reference beam that includes two mutually orthogonal first and second linear polarized waves, and a circular polarized signal beam that includes two mutually orthogonal first and second linear polarized waves, a movable mirror unit for reflecting the reference beam back to said beam splitter and producing a Doppler frequency shift of the reference beam, the signal beam being directed to the specimen, being reflected by an imaging plane in the specimen back to said beam splitter, and containing measured information of the imaging plane in the specimen, said beam splitter further combining the reference beam reflected by said movable mirror unit and the signal beam reflected by the imaging plane in the specimen into a combined output beam, a first polarization beam splitter for separating the combined output beam from said beam splitter into mutually orthogonal linear-polarized first and second optical signals, the first optical signal corresponding to the first linear polarized waves of the signal and reference beams, the second optical signal corresponding to the second linear polarized waves of the signal and reference beams, and first and second photo detectors for detecting the first and second optical signals from said first polarization beam splitter, respectively, so as to generate a first optical heterodyne electrical signal output corresponding to the first optical signal, and a second optical heterodyne electrical signal output corresponding to the second optical signal, respectively; a differential amplifier being coupled to said first and second photo detectors of said polarized heterodyne interferometer for receiving the first and second optical heterodyne electrical signal outputs therefrom, and generating a differential signal output therefrom; a data acquisition unit being coupled to said first and second photo detectors of said polarized heterodyne interferometer and said differential amplifier for receiving the first and second optical heterodyne electrical signal outputs and the differential signal output therefrom, and for measuring amplitudes of the first and second optical heterodyne electrical signal outputs and the differential signal output; and a computing unit that is coupled to said data acquisition unit, and that is operable to compute the amplitudes measured by said data acquisition unit to determine at least one parameter corresponding to the measured information of the specimen.