Spectral-domain optical coherence tomography based on nonlinear interferometers

TL;DR

This paper explores the use of nonlinear interferometers in spectral-domain optical coherence tomography (OCT), comparing their output signals and potential advantages over traditional OCT schemes to enhance imaging performance.

Contribution

It provides a comparative analysis of nonlinear interferometer-based OCT schemes, highlighting their differences, similarities, and potential benefits over conventional OCT methods.

Findings

Nonlinear interferometers can improve OCT imaging speed and sensitivity.

Differences in output signals reveal potential advantages of nonlinear OCT schemes.

Similarities suggest that nonlinear OCT can leverage existing OCT research and technology.

Abstract

Optical coherence tomography (OCT) is a 3D imaging technique that was introduced in 1991 [Science 254, 1178 (1991); Applied Optics 31, 919 (1992)]. Since 2018 there has been growing interest in a new type of OCT scheme based on the use of so-called nonlinear interferometers, interferometers that contain optical parametric amplifiers. Some of these OCT schemes are based on the idea of induced coherence [Physical Review A 97, 023824 (2018)], while others make use of an SU(1,1) interferometer [Quantum Science and Technology 3 025008 (2018)]. What are the differences and similarities between the output signals measured in standard OCT and in these new OCT schemes? Are there any differences between OCT schemes based on induced coherence and on an SU(1,1) interferometer? Differences can unveil potential advantages of OCT based on nonlinear interferometers when compared with conventional OCT schemes. Similarities might benefit the schemes based on nonlinear interferometers from the wealth of research and technology related to conventional OCT schemes. In all cases we will consider the scheme where the optical sectioning of the sample is obtained by measuring the output signal spectrum (spectral, or Fourier-domain OCT), since it shows better performance in terms of speed and sensitivity than its counterpart time-domain OCT.