# Nanophotonic supercontinuum based mid-infrared dual-comb spectroscopy

## TL;DR

This paper introduces a simplified, broadband mid-infrared dual-comb spectroscopy method using nanophotonic supercontinuum generation, enabling high-resolution, rapid molecular detection across a wide spectral range.

## Contribution

It presents a novel nanophotonic dispersion engineering technique for flat, ultra-broadband mid-IR comb spectra, advancing dual-comb spectroscopy capabilities.

## Key findings

- Achieved >100,000 comb lines in 2800-3600 1/cm range
- Enabled resolution of isotopologues in functional groups
- Demonstrated high sensitivity, spectral resolution, and speed

## Abstract

High resolution and fast detection of molecular vibrational absorption is important for organic synthesis, pharmaceutical process and environmental monitoring, and is enabled by mid-infrared (mid-IR) laser frequency combs via dual-comb spectroscopy. Here, we demonstrate a novel and highly simplified approach to broadband mid-IR dual-comb spectroscopy via supercontinuum generation, achieved using unprecedented nanophotonic dispersion engineering that allows for flat-envelope, ultra-broadband mid-IR comb spectra. The mid-IR dual-comb has an instantaneous bandwidth covering the functional group region from 2800-3600 1/cm, comprising more than 100,000 comb lines, enabling parallel gas-phase detection with a high sensitivity, spectral resolution, and speed. In addition to the traditional functional groups, their isotopologues are also resolved in the supercontinuum based dual-comb spectroscopy. Our approach combines well established fiber laser combs, digital coherent data averaging, and integrated nonlinear photonics, each in itself a state-of-the-art technology, signalling the emergence of mid-IR dual-comb spectroscopy for use outside of the protected laboratory environment.