Multiheterodyne spectroscopy using interband cascade lasers

TL;DR

This paper demonstrates a compact, energy-efficient multiheterodyne spectroscopy system using interband cascade lasers, achieving high spectral resolution and broadband coverage suitable for portable chemical sensing in the mid-infrared.

Contribution

It introduces a novel multiheterodyne spectroscopy setup with interband cascade lasers, combining broadband spectral coverage, high resolution, and low power consumption.

Findings

Achieved up to 30 mW optical power with less than 0.5 W electrical power consumption.

Demonstrated high-resolution spectroscopy with kHz linewidths and 30 dB SNR improvement.

Performed rapid broadband spectroscopic assessments of ethylene and methane.

Abstract

While mid-infrared radiation can be used to identify and quantify numerous chemical species, contemporary broadband mid-IR spectroscopic systems are often hindered by large footprints, moving parts and high power consumption. In this work, we demonstrate multiheterodyne spectroscopy using interband cascade lasers, which combines broadband spectral coverage with high spectral resolution and energy-efficient operation. The lasers generate up to 30 mW of continuous wave optical power while consuming less than 0.5 W of electrical power. A computational phase and timing correction algorithm is used to obtain kHz linewidths of the multiheterodyne beat notes and up to 30 dB improvement in signal-to-noise ratio. The versatility of the multiheterodyne technique is demonstrated by performing both rapidly swept absorption and dispersion spectroscopic assessments of low-pressure ethylene (C$_2$H$_4$) acquired by extracting a single beat note from the multiheterodyne signal, as well as broadband multiheterodyne spectroscopy of methane (CH$_4$) acquired with all available beat notes with microsecond temporal resolution and an instantaneous optical bandwidth of 240 GHz. The technology shows excellent potential for portable and high-resolution solid state spectroscopic chemical sensors operating in the mid-infrared.