Parameter Estimation in QOCT

Quantum optical coherence tomography (QOCT) exploits an entangled twin-photon light source to carry out axial optical sectioning. In this work we present a novel method that by the use of QOCT interferometric data from a given layered medium, can produce the internal structure of the sample. We formulate the problem of retrieving the internal structure of the layered sample in QOCT as a parameter estimation problem. Our parameter estimation approach utilizes the QOCT observation model and determines the following model parameters: the positions of reflecting surfaces of the sample, refractive indices, and group-velocity dispersion (GVD) coefficients of the layers. We applied our method to closely spaced layered samples (fused silica windows). Our experiments demonstrated the capability of our numerical technique to retrieve the correct structure of the sample as well as further improve the axial resolution of the QOCT signal. In particular, we have shown that our method can recover the correct layer positions in the complicated case of the closely spaced layered sample where the direct visual examination would fail to determine the correct values of layer positions. We test our method against both simulated and real data.