Theoretical Investigation on the Mechanism and Law of Broadband Terahertz Wave Detection Using Rydberg Quantum State

The bandwidth and sensitivity of traditional terahertz detection devices are limited by material properties and working temperature. Here, we proposed a four-level Rydberg atom detection method, which can realize real-time detection for the absolute strength of the terahertz electric field under room temperature with the detection bandwidth of 0-5 THz. By theoretical analysis and formula derivation, the relation among the terahertz electric field strength, excitation energy level, coupling photoelectric field strength, gas cell temperature and electromagnetically induced transparency (EIT) signal are studied in detailed. The NEP of this method is proven to be 10 ⁻¹⁷ W/Hz ^1/2 in the range of 0-1 THz, which is three orders of magnitude smaller than that of the traditional optimal thermal detection system. This research has important reference value for the later high-sensitivity detection and application development of terahertz waves