Investigations of Rydberg-Atom Based THz-Wave Electric Field Sensor

We have started research on Rydberg-atom based sensor, which is capable of SI-traceable electric field measurements of Terahertz waves. The ladder-type EIT (Electromagnetically Induced Transparency) signals were prepared by counterpropagating lasers of two distinct wavelength lasers corresponding to the S-P-D transitions of Cesium (Cs) atoms enclosed in a cylindrical glass cell. Irradiation of a THz-wave whose frequency matched the D-F transition then results in an observed Autler-Townes (AT) splitting of the EIT signal. We confirmed that the frequency separation of the splitting changes with the irradiated power of the 100GHz and 300 waves.