Optical coherence tomography with an SU(1,1) interferometer in the high parametric gain regime

Optical coherence tomography (OCT) is a highly successful 3D imaging technique that was put forward in 1991 Standard OCT schemes make use of a Michelson interferometer, and achieve high axial resolution using light with a large bandwidth. In the last few years, there has been a growing interest in a new type of OCT schemes that uses so-called nonlinear interferometers based on optical parametric amplifiers. Some of these OCT schemes are based on the idea of induced coherence, a particular class of nonlinear interferometer originally introduced the very same year as OCT. Other schemes are based on an SU(1,1) interferometer. All of these experimental demonstrations have been done in the low parametric gain regime, where the low energy available requires long integration times to achieve high quality imaging. In this regime one needs to use single photon counting modules for signal detection. We show that one can do optical coherence tomography based on an SU(1,1) nonlinear interferometer with high-gain parametric down-conversion. For imaging and sensing applications, this scheme promises to outperform previous experiments working at low arametric gain, since higher photon fluxes provide better sensitivity and lower integration times for obtaining high-quality images. Moreover, there is no need to use single-photon detectors and standard spectrometers can be used instead.