Highly sensitive Rydberg atom-based terahertz heterodyne receiver enabled by array-beam excitation

Rydberg atom-based precision terahertz (THz) metrology has advanced rapidly in recent years. However, its electric-field sensitivity remains significantly lower than that of state-of-the-art THz receivers, thereby limiting its potential for practical applications. In this work, we enhance the sensitivity of a Rydberg atom-based THz heterodyne receiver at 0.3 THz by employing a 3 × 3 laser-beam array, yielding a 7.6 dB improvement over a single-beam configuration. The achieved electric-field sensitivity reaches 35.8±1.4 nV cm^-1 Hz^-1/2, approaching the performance of an ideal λ/2 metallic antenna. A minimum-detectable power of -149 dBm is achieved at a 1-Hz bandwidth. Our results suggest a promising approach for future THz radar and communication applications.