Frequency chirped Fourier-Transform spectroscopy

At the beginning of 2023 researchers from Institute for Quantum Electronics, Zürich, Switzerland published in Nature an article where they describe a Frequency chirped Fourier-Transform (FT) spectrometer that can perform Mid-IR dual-comb spectroscopy using VIGO detector.

Scientists point out the problem of simultaneous high spectral and temporal resolution of FT spectrometers caused by the linear translation of a scanning mirror. They present an FT spectrometer whose operational principle is based on continuous rotational motion of the scanning mirror. As a result, they obtained effectively decoupling the spectral resolution from the temporal one. The system performs Mid-IR dual-comb spectroscopy with a single comb source since the Doppler-shifted version of the comb serves as the second comb.

Researchers use thermo-electrically cooled HgCdTe detectors

PVMI-4TE-10.6-1×1 made in VIGO Photonics to obtain interferograms in the rotational FT spectrometer. As a light source, they use the mid-IR quantum cascade laser (QCL) frequency comb emitting around 8 μm wavelength. Two VIGO detectors obtain sample and normalization interferograms of the QCL and a third one registered a reference interferogram of the continuous wave laser.

The presented system can be a promising option for applications where high speed, large optical bandwidth, and high spectral resolution are desired by integrating mulitple broadband sources such as ultra broadband white, NIR and mid-IR supercontinuum laser sources.

Link to the article