Gapless dual-comb spectroscopy in terahertz region

TL;DR

This paper introduces a novel gapless dual-comb spectroscopy technique in the terahertz region, achieving high spectral resolution and accuracy by interpolating between comb teeth, enabling advanced THz spectroscopic analysis.

Contribution

The authors developed a gapless THz comb by interpolating between comb teeth, enabling dual-comb spectroscopy with enhanced resolution and accuracy in the THz range.

Findings

Spectral resolution achieved was 2.5 MHz.

Spectral accuracy was improved to 10^-6.

Demonstrated effective low-pressure gas spectroscopy.

Abstract

We demonstrated combination of gapless terahertz (THz) comb with dual-comb spectroscopy, namely gapless dual-THz-comb spectroscopy, to achieve the spectral resolution equal to width of the THz comb tooth. The gapless THz comb was realized by interpolating frequency gaps between the comb teeth with sweeping of a laser mode-locked frequency. The demonstration of low-pressure gas spectroscopy with gapless dual-THz-comb spectroscopy clearly indicated that the spectral resolution was decreased down to 2.5-MHz width of the comb tooth and the spectral accuracy was enhanced to 10-6 within the spectral range of 1THz. The proposed method will be a powerful tool to simultaneously achieve high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.