Mid-infrared optical coherence tomography with a stabilized OP-GaP optical parametric oscillator

We demonstrate mid -infrared time -domain optical coherence tomography (OCT) with an orientation -patterned GaP optical parametric oscillator. Instantaneous broadband mid -infrared spectra provide reduced scattering for OCT applications including cultural heritage, quality assurance, and security. B -scan calibrations performed across the wavelength tuning range show depth resolutions of 67 mu m at 5.1 mu m and 88 mu m at 10.5 mu m. Volumetric imaging inside a plastic bank card is demonstrated at 5.1 mu m, with a 1 Hz A -scan rate that indicates the potential of stable broadband OPO sources to contribute to mid -infrared OCT.