Microwave Electric Fields Measurement Using One-dimensional Standing-wave Coupling Light Of Rydberg EIT

Compared with ground-state atoms,Rydberg atoms have a larger distance between the outer electrons and the nucleus.The nucleus more weakly binds the electrons,so the external electric fields has a more significant influence on the outer electrons of Rydberg atoms,and the Rydberg energy level with adjacent principal quantum numbers is closely spaced,covering the microwave to terahertz bands（～GHz-THz）.Therefore,the research on precision measurement and sensing of microwave electric fields using Rydberg atoms is becoming a new hot topic at home and abroad.This paper presents comprehensive research for microwave electric fields measurements based on the coherent enhancement of a one-dimensional standing wave field of coupling light based on the electromagnetic induction with Rydberg atoms.A three-level system of cesium atoms at room temperature is constructed.At first,the cesium atoms in the ground-state(6S_1/2)are excited to the immediate state(6P_3/2)by a diode laser（probe light,～852nm）.Secondly,a 510nm laser（coupling light）exited the immediate state atoms to the specific Rydberg state(48D_5/2).The transmission of the probe light,which is derived from the electromagnetic-induced three-level ladder-type atomic system,is recorded.In an vapor cell with the antireflection film coating at the wavelength of coupling light,the one-dimensional standing wave field of coupling light is achieved using a mode-matching reflection optical path.The influence of the coherent enhancement of the one-dimensional standing wave coupling light field on the electromagnetically induced transparency transmission is observed and analyzed.Then,the cesium atoms are coupling with the nearby Rydberg state by the incoming microwave electric field.The microwave electric field in the four-level atomic system causes the splitting of the probe laser’s transmission spectrum,known as Autler-Townes splitting.The coherent enhancement of the one-dimensional standing wave coupling light field on the EIT-AT splitting spectrum is observed.The strength of microwave electric field with amplitude modulation is measured using the spectrum analyzer.The effect of introducing a one-dimensional standing wave field on the signal-to-noise ratio and frequency response characteristic curve of microwave electric field measurements was evaluated.The specific content includes several aspects:A-T splitting is presented in four-level stepped systems,followed by the EIT.At the same time,the coherent enhancement of the coupling light fields is analyzed theoretically,and the principle of coherent enhancement of the one-dimensional standing wave coupling light fields is expounded.Obtaining EIT and A-T splitting signals requires three-level or four-level EIT systems under the coherent enhancement of the one-dimensional standing wave coupling light fields.The microwave electric fields were used to measure the system.The results show that,under the condition that the intensity of the incident coupling light remains unchanged,one-dimensional standing wave coupling light fields can improve the signal-to-noise ratio and bandwidth at a lower microwave power by increasing the standing wave coupling light fields and the formation of the one-dimensional standing wave fields at a higher microwave power can effectively eliminate the bimodal feature and present a flatter response feature.Finally,this paper summarizes microwave electric fields measurement using on e-dimensional standing wave coupling light of Rydberg EIT,puts forward the further research direction,and looks forward to the research of the Rydberg atomic quantum precision measurement,which has significant reference value for the realization of low power consumption,flat frequency response curve and microwave electric fields measurement sensor.