Patent ID: 6882431

Claim:
An optical apparatus for collecting quantum optical coherence tomography data from a semi-reflective object comprising: a source of entangled photons, said source generating a plurality of photon pairs (twinons), each of said twinons comprising a first twin photon and a second twin photon, said first twin photon being correlated to said second twin photon in at least one of time, wavelength and polarization; a separation element in optical communication with said source, the separation element providing a first optical path and second optical path, the first optical path including the semi-reflective object, said separation element being unable to distinguish the properties of the photons entering the first and second optical paths; a remixing element in optical communication with both the first optical path and the second optical path, the remixing element comprising a pre-determined beamsplitting ratio, an input aperture, a first output aperture, and a second output aperture, said remixing element providing a third optical path and a fourth optical path, wherein the plurality of twinons entering the input aperture are re-emitted through both the first output aperture into the third optical path and the second output aperture into the fourth optical path, the twinons being emitted in statistical proportion in accordance with the beamsplitting ratio of the remixing element; a variable optical time-delay element, said delay element located in one optical path; a first detector, said first detector in optical communication with the first output aperture along the third optical path; a second detector, said second detector in optical communication with the second output aperture along the fourth optical path; a signal processor adapted to identify coincident detections of photons at the two detectors; wherein twinons from the source of entangled photons are emitted into the first and second optical paths, the photons in the first optical path being reflected from the semi-reflective object; the photons in the two optical paths being combined indistinguishably at the remixing element and being re-emitted at the remixing element into the third and fourth optical paths; the photons in the third optical path being detected by the first detector and the photons in the fourth optical path being detected by the second detector; the variable optical time-delay element, being pre-adjusted to a value, T, within a predetermined range, delaying the photons passing through it by T; and the signal processor identifying and determining the rate of coincident photon detections on the two detectors for the delay value T.