QUANTUM FIELD OCT APPROACH

SeE: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5976263/

Major advances in optical coherence tomography (OCT) imaging are likely to occur through a quantum field approach to the technology. In this paper, which is the first part in a series on the topic, the quantum basis of OCT first order correlations is expressed in terms of full field quantization. Specifically first order correlations (FOC) are treated as the linear sum of single photon interferences along indistinguishable paths. Photons and the electromagnetic (EM) field are described in terms of quantum harmonic oscillators.  The approach is similar to that used by groups detecting gravitational waves.  Here single photons can only interfere with themselves.  In the paper, ranging errors are discussed (with remedies) from vacuum fluctuations through the detector port, photon counting errors, and position probability amplitude uncertainty. In addition, the principles of quantum field theory and first order correlations are needed for studying second order correlations.  This author objects using the term quantum OCT for entangled photon embodiments.  These are SOC, have macroscopic quantum properties unlike FOC, and involve joint detection between two detectors.