Frequency comb spectroscopy

TL;DR

Frequency comb spectroscopy leverages broad, equidistant laser spectra to significantly enhance spectroscopic measurements, enabling high-precision, broad-range, and potentially portable spectrometers for scientific and practical applications.

Contribution

This review summarizes recent advances in atomic and molecular broadband spectroscopy using frequency combs, highlighting new instrument types and applications.

Findings

Enhanced spectral measurement accuracy with frequency combs

Development of dual-comb spectrometers without moving parts

Potential for portable, chip-scale spectrometers for real-time sensing

Abstract

A laser frequency combs is a broad spectrum composed of equidistant narrow lines. Initially invented for frequency metrology, such combs enable new approaches to spectroscopy over broad spectral bandwidths, of particular relevance to molecules. With optical frequency combs, the performance of existing spectrometers, such as Michelson-based Fourier transform interferometers or crossed dispersers, involving e.g. virtual imaging phase array (VIPA) \'etalons, is dramatically enhanced. Novel types of instruments, such as dual-comb spectrometers, lead to a new class of devices without moving parts for accurate measurements over broad spectral ranges. The direct self-calibration of the frequency scale of the spectra within the accuracy of an atomic clock and the negligible contribution of the instrumental line-shape will enable determinations of all spectral parameters with high accuracy for stringent comparisons with theories in atomic and molecular physics. Chip-scale frequency-comb spectrometers promise integrated devices for real-time sensing in analytical chemistry and biomedicine. This review article gives a summary of advances in the emerging and rapidly advancing field of atomic and molecular broadband spectroscopy with frequency combs.