Unifying frequency metrology across microwave, optical, and free-electron domains
Abstract
Frequency metrology lies at the heart of precision measurement. Optical frequency combs provide a coherent link uniting the microwave and optical domains in the electromagnetic spectrum, with profound implications in timekeeping, sensing and spectroscopy, fundamental physics tests, exoplanet search, and light detection and ranging. Here, we extend this frequency link to free electrons by coherent modulation of the electron phase by a continuous-wave laser locked to a fully stabilized optical frequency comb. Microwave frequency standards are transferred to the optical domain via the frequency comb, and are further imprinted in the electron spectrum by optically modulating the electron phase with a photonic chip-based microresonator. As a proof-of-concept demonstration, we apply this frequency link in the calibration of an electron spectrometer, and use the electron spectrum to measure the optical frequency. Our work bridges frequency domains differed by a factor of and carried by different physical objects, establishes a spectroscopic connection between electromagnetic waves and free-electron matter waves, and has direct ramifications in ultrahigh-precision electron spectroscopy.
Keywords
Cite
@article{arxiv.2403.10486,
title = {Unifying frequency metrology across microwave, optical, and free-electron domains},
author = {Yujia Yang and Paolo Cattaneo and Arslan S. Raja and Bruce Weaver and Rui Ning Wang and Alexey Sapozhnik and Fabrizio Carbone and Thomas LaGrange and Tobias J. Kippenberg},
journal= {arXiv preprint arXiv:2403.10486},
year = {2024}
}