Nonlinearity of Microwave Electric Field Coupled Rydberg Electromagnetically Induced Transparency and Autler-Townes Splitting

Liping Hao,Jianming Zhao,Yuechun Jiao,Yongmei Xue,Jiabei Fan,Suotang Jia

doi:10.3390/app9081720

Abstract

An electromagnetically induced transparency (EIT) of a cascade-three-level atom involving Rydberg level in a room-temperature cell, formed with a cesium 6 S 1 / 2 -6 P 3 / 2 -66 S 1 / 2 scheme, is employed to detect the Autler-Townes (AT) splitting resulted with a 15.21-GHz microwave field coupling the 66 S 1 / 2 →65 P 1 / 2 transition. Microwave field induced AT splitting, f A T , is characterized by the distance of peak-to-peak of an EIT-AT spectrum. The f A T dependence on the microwave Rabi frequency, Ω M W , demonstrates two regions, the strong-coupling linear region, f A T ≈ Ω M W and the weak-coupling nonlinear region, f A T ≲ Ω M W . The f A T dependencies on the probe and coupling Rabi frequency are also investigated. Using small probe- and coupling-laser, the Rabi frequency is found to enlarge the linear regime and decrease the uncertainty of the microwave field measurements. The measurements agree with the calculations based on a four-level atomic model.

Highlights

Atom-based measurements are receiving increasing attention, such as time [1], gravity [2]and electromagnetic fields [3,4,5], due to their invariable level structures that can be used as self calibrating criterions for measurements of these quantities
The electromagnetically induced transparency (EIT) line splits into two-peak spectra, known as AT effect, when we apply a microwave electric field that couples |66S1/2 i → |65P1/2 i transition
We find that the nonlinear region depends on the microwave-free EIT linewidth

Summary

Introduction

Electromagnetic fields [3,4,5], due to their invariable level structures that can be used as self calibrating criterions for measurements of these quantities. Rydberg EIT can be used to measure a large dynamic range of the electric fields of electromagnetic radiation, including microwave fields [10,11,12], millimeter waves [13], static electric fields [14,15] and subwavelength imaging of microwave electric-field distributions [18,19] and field inhomogeneities [20]. Measurement of the microwave field for frequency larger than 1 GHz is mainly based on an Autler-Townes (AT) effect [21] that is induced by the microwave field coupling nearby Rydberg levels [10]. Rydberg-EIT is employed to measure the AT splitting ( f AT ) that is proportional to the μ

Methods

Results

Conclusion