Rydberg-Atom Sensors Enable High-Resolution Terahertz Frequency Detection and Precision Spectroscopy

Terahertz (THz) frequency detection and precision spectroscopy have transformative potential for applications across meteorology, cosmology, and medicine. Although intrinsic atomic transition frequencies provide an ideal basis for ultraprecise frequency measurements, leveraging atoms for THz-frequency detection remains technically demanding. Here, we demonstrate high-resolution frequency detection and spectroscopy within the 530–580 GHz band using electromagnetically induced atomic fluorescence spectra. The experimental results are consistent with theoretical predictions. By integrating deep learning models, the proposed Rydberg-atom sensor achieves a frequency resolution of 1 MHz over the entire THz detuning range. Furthermore, we employ this sensor to measure the THz transmission spectrum of a bound state in the continuum metasurface, achieving a world-record high quality factor of 24,900. These results highlights the emerging capability of Rydberg atoms to function as versatile THz sensors, opening new frontiers in THz spectroscopic research.