Ultrawideband dynamic microwave frequency-amplitude measurement.

Microwave measurement is crucial in various fields, such as communication, radar, and cognitive radio, now poised for a revolution with the advent of photonic-assisted techniques that promise unprecedented performance. However, existing methods often disrupt the amplitude integrity of unknown signals and rely on time-consuming frequency sweeping to achieve multifrequency detection, which markedly restricts their instantaneous bandwidth, response speed, and accuracy. Here, we present a groundbreaking approach leveraging digital optical frequency comb-enabled stimulated Brillouin scattering to achieve instantaneous microwave frequency and amplitude detection, attaining a record-breaking 50.8-gigahertz bandwidth, a 1.1-megahertz accuracy, and a 500-nanosecond temporal resolution, which is three orders of magnitude improvement over that obtained with frequency sweeping schemes. In addition to conventional frequency detection, the proposed technique enables simultaneous multifrequency microwave amplitude measurement and achieves a substantial performance enhancement in the figure of merit of more than 10-fold, which paves the way for dynamic microwave signal detection and analysis.