High resolution mid-infrared optical coherence tomography with kHz line rate

TL;DR

This paper presents a high-resolution mid-infrared OCT system operating at 4 μm with a record 3 kHz A-scan rate, enabling fast imaging with sub-micron axial resolution for applications like micro-mapping and gas monitoring.

Contribution

The authors developed a MIR OCT system with collinear sum-frequency upconversion achieving a 3 kHz scan rate and record axial resolution, advancing imaging speed and resolution in the mid-infrared range.

Findings

Achieved 8.6 μm axial resolution in MIR OCT.

Recorded a 5.8 μm axial resolution with enhanced imaging.

Demonstrated real-time CO₂ monitoring alongside OCT imaging.

Abstract

We report on Mid-infrared (MIR) OCT at 4 $\mu$m based on collinear sum-frequency upconversion and promote the A-scan scan rate to 3 kHz. We demonstrate the increased imaging speed for two spectral realizations, one providing an axial resolution of 8.6 $\mu$m, and one providing a record axial resolution of 5.8 $\mu$m. Image performance is evaluated by sub-surface micro-mapping of a plastic glove and real-time monitoring of CO$_2$ in parallel with OCT imaging.