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

Area of Science:

• Optics and Photonics
• Biomedical Imaging

Background:

• Mid-infrared (MIR) light offers reduced scattering compared to near-infrared light, enabling deeper penetration and clearer imaging.
• Optical Coherence Tomography (OCT) is a powerful non-invasive imaging technique, but its application in the MIR spectrum has been limited by source availability.

Purpose of the Study:

• To demonstrate the feasibility of time-domain optical coherence tomography (OCT) in the mid-infrared (MIR) spectral range.
• To showcase the capabilities of a novel orientation-patterned Gallium Phosphide (GaP) optical parametric oscillator (OPO) as a light source for MIR OCT.

Main Methods:

• Utilized an orientation-patterned GaP optical parametric oscillator (OPO) to generate instantaneous broadband MIR spectra.
• Performed B-scan calibrations across the OPO's wavelength tuning range to assess depth resolution.
• Demonstrated volumetric imaging within a plastic bank card at 5.1 µm.

Main Results:

• Achieved depth resolutions of 67 µm at 5.1 µm and 88 µm at 10.5 µm.
• Successfully performed volumetric imaging of a plastic bank card at 5.1 µm.
• Operated the system at an A-scan rate of 1 Hz, indicating system stability and potential for real-time imaging.

Conclusions:

• The developed MIR OCT system, powered by a broadband OPO source, shows significant potential for various applications.
• Reduced scattering in the MIR spectrum enhances imaging capabilities for cultural heritage, quality assurance, and security.
• Stable broadband OPO sources are crucial for advancing MIR OCT technology.