A high-resolution microresonator-frequency-comb spectrometer

TL;DR

This paper introduces a microresonator-based spectrometer that combines soliton microcombs with parallel detection to achieve high resolution and wide bandwidth in a compact, robust device suitable for various scientific applications.

Contribution

It presents a novel spectrometer design integrating dissipative Kerr solitons with parallel detection, overcoming traditional trade-offs in resolution, bandwidth, and speed.

Findings

Achieves 200-kHz resolution over 4 THz bandwidth

Uses a fully stabilized broadband soliton microcomb

Operates with minutes-level processing time and environmental robustness

Abstract

Spectral analysis is one of the most powerful technologies for studying and understanding matter. As the devices for spectral analysis, spectrometers are widely used in material detection, isotope analysis, trace gas detection, and the study of atomic and molecular hyperfine structures. While high resolution, wide bandwidth and fast speed are essential factors, they are always trade-offs for conventional spectrometers. Here, we present a soliton-microcomb-based spectrometer that overcomes these challenges by integrating dissipative Kerr solitons (DKSs) with double-sideband modulation and parallelized detection. Leveraging a high-quality silicon nitride microresonator, we generate a broadband, fully stabilized soliton microcomb and employ radio-frequency-modulated double sidebands to scan the optical spectrum with the resolution constrained only by the comb-line linewidth. By projecting the comb lines onto a two-dimensional charge-coupled device (CCD) via a virtually imaged phased array (VIPA)-grating system, we enable parallel processing of all spectral components, circumventing sequential scanning delays. The resulting spectrometer achieves 200-kHz resolution across a 4-THz bandwidth with minutes-level processing time while maintaining robustness against environmental fluctuations. Being promising for miniaturization, this work bridges the gap between laboratory-grade performance and field-deployable practicality, unlocking new possibilities for spectroscopy in astronomy, metrology, and integrated photonics.