Time-encoded mid-infrared Fourier-domain optical coherence tomography

TL;DR

This paper introduces a simple, high-resolution, high-sensitivity Fourier-domain OCT system operating in the mid-infrared range, utilizing an InF3 supercontinuum source and a specialized dispersive spectrometer for imaging applications.

Contribution

The work presents a novel, cost-effective mid-infrared OCT system with improved resolution and sensitivity, capable of imaging porous ceramics and green parts in manufacturing.

Findings

Achieved axial resolution below 8 micrometers.

Sensitivity over 80 dB in mid-IR OCT imaging.

Demonstrated effective imaging with a low-power supercontinuum source.

Abstract

We report on a technically simple approach to achieve high-resolution and high-sensitivity Fourier-domain OCT imaging in the mid-infrared range. The proposed OCT system employs an InF3 supercontinuum source. A specially designed dispersive scanning spectrometer based on a single InAsSb point detector is employed for detection. The spectrometer enables structural OCT imaging in the spectral range from 3140 nm to 4190 nm with a characteristic sensitivity of over 80 dB and an axial resolution below 8 um. The capabilities of the system are demonstrated for imaging of porous ceramic samples and transition-stage green parts fabricated using an emerging method of lithography-based ceramic manufacturing. Additionally, we demonstrate the performance and flexibility of the system by OCT imaging using an inexpensive low-power (average power of 16 mW above 3 um wavelength) mid-IR supercontinuum source.