Photonics Spectra Conference 2021 – Rapid Reaction Monitoring via QCL-Based Mid-IR Dual-Comb Spectroscopy

Understanding the mechanism of a chemical reaction is an important step away from trial-and-error-based reaction optimization. By studying the structures of intermediates — how long they exist and the ways in which they can and cannot react — reactions can be intelligently designed and controlled. Infrared absorption is a prime choice for such reaction monitoring tasks due to its sensitivity and specificity. However, the achievable speed is often limited by the available instrumentation.

Dual-comb spectroscopy (DCS) based on quantum cascade laser (QCL) frequency combs has become a major contender in application spaces previously dominated by Fourier transform infrared (FTIR) spectrometers. QCL DCS has led to a paradigm shift in applications that previously relied on step-scan techniques, such as protein dynamic analysis and spectroelectrochemistry.

In this presentation, Hugi focuses on the high signal-to-noise ratios that can be achieved at millisecond timescales, without experiment repetition, using dual-comb spectroscopy based on QCLs. Continuous reaction monitoring with 220 spectra/s can be achieved with a high spectral resolution >0.3 cm^-1. Pushing the DCS technique, Hugi and colleagues manage to get sub-µs time resolution for up to 128 ms acquisition time. Furthermore, the team has improved the spectral coverage of QCL DCS covering >100 cm^-1. The IRis-F1 combines all these features in a single instrument, resulting in versatility that paves the way to the next-generation mid-infrared spectroscopy instrumentation.

This presentation is part of the 2021 Photonics Spectra Conference.