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

We report on mid-infrared optical coherence tomography (OCT) at 4 µm 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 µm, and one providing a record axial resolution of 5.8 µm. Image performance is evaluated by sub-surface micro-mapping of a plastic glove and real-time monitoring of  in parallel with OCT imaging.