Mid-infrared dual-comb spectroscopy with low drive-power on-chip sources

TL;DR

This paper demonstrates a compact, low-power on-chip dual-comb spectrometer operating in the mid-infrared 3-4 μm range, capable of high-sensitivity gas detection suitable for portable applications.

Contribution

It introduces semiconductor-based dual-comb sources with less than 1 W power consumption for mid-infrared spectroscopy, enabling portable and efficient broadband sensing.

Findings

Achieved high-sensitivity methane and HCl detection.

Spectral coverage of 33 cm$^{-1}$ with 0.32 cm$^{-1}$ sampling.

Peak SNR of ~100 at 100 μs integration.

Abstract

Two semiconductor optical frequency combs consuming less than 1 W of electrical power are used to demonstrate high-sensitivity mid-infrared dual-comb spectroscopy in the important 3-4 $\mu$m spectral region. The devices are 4 millimeters long by 4 microns wide, and each emits 8 mW of average optical power. The spectroscopic sensing performance is demonstrated by measurements of methane and hydrogen chloride with a spectral coverage of 33 cm$^{-1}$ (1 THz), 0.32 cm$^{-1}$ (9.7 GHz) frequency sampling interval, and peak signal-to-noise ratio of ~100 at 100 $\mu$s integration time. The monolithic design, low drive power, and direct generation of mid-infrared radiation are highly attractive for portable broadband spectroscopic instrumentation in future terrestrial and space applications.