Spectroscopy of the Rydberg states in a two-frequency laser field

Jinlian Hu, Yuechun Jiao, Yunhui He +6 more

Abstract We investigate the response bandwidth of a superheterodyne Rydberg receiver at a room-temperature vapor cell, and present an architecture of atomic array to increase the response bandwidth. Two microwave fields, denoted as a local oscillator (LO) ELO and a signal field ESig, couple two Rydberg states transition of |52D5/2⟩ → |53P3/2⟩. In the presence of the LO field, the frequency difference between two fields can be read out as an intermediate frequency (IF) signal using Rydberg electromagnetically induced transparency (EIT) spectroscopy. The bandwidth of the Rydberg receiver is obtained by measuring the output power of IF signal versus the frequency difference between two fields. The bandwidth dependence on the Rabi frequency of excitation lasers is presented, which shows the bandwidth decrease with the Rabi frequency of probe laser, while it is quadratic dependence on the Rabi frequency of coupling laser. Meanwhile, we investigate the effect of probe laser waist on the bandwidth, showing that the bandwidth is inversely proportional to the laser waist. We achieve a maximum response bandwidth of the receiver about 6.8~MHz. Finally, we design an architecture of atomic array for increasing the response and keeping the sensitivity, simultaneously. Our work has the potential to extend the applications of Rydberg atoms in communications.

G. Alber, P. Zoller

Li Jing-Kui, Yang Wen-Guang, Zhenfei Song +4 more

Rydberg atoms, with large principal quantum number, exhibit certain properties, such as long lifetimes and strong interactions with fields and other atoms, which have been extensively investigated recently. One of the properties is the electromagnetically induced transparency (EIT) of Rydberg ladder system, which can be used to measure the radio frequency (RF) field with high sensitivity. In this paper, we investigate the quantum coherent effect of cesium Rydberg atom in a three-level ladder system involving the ground state (6S1/2), the excited state (6P3/2) and 49S1/2 Rydberg state in room temperature vapor cell. The probe laser (852 nm) drives the transition of 6S1/2(F=4)→6P3/2(F'=5), while the coupling laser (510 nm) couples the Rydberg transition of 6P3/2 (F'=5)→nS1/2. A typical electromagnetically induced transparency spectrum is obtained when the weak probe laser is scanned through the transition of 6S1/2(F=4)→6P3/2(F'=5) and the coupling laser tuning to Rydberg transition. The two-photon RF spectra are observed when the RF field with a frequency of ～16.9 GHz couples the Rydberg transition of 49S1/2→47D3/2, where the EIT signal is split into two EIT peaks due to the interaction between the RF field and Rydberg atoms. The dependences of EIT splitting on the power of RF field are investigated. The results show that the EIT splitting increases with the power of RF field, which can inversely be used to measure the RF field with a higher spatial resolution in the future.

Claude Fabre, S. Haroche

Joel Venzke, Brynn Reiff, Zetong Xue +3 more

Peng Xu, Chen Xii, Wang Jin +1 more

Frequency stabilization of a diode laser at 480 nm is crucial for coherently exciting rubidium atoms to Rydberg states.A laser frequency stabilization technique is reported based on electromagnetically induced transparency in a ladder configuration with a polarization spectrum stabilized 780 nm diode laser as the probe laser and a 480 nm laser as the coupling laser.With a uniform magnetic field,a two-photon dichroic atomic vapor laser lock(DAVLL) spectroscopy was generated.Then this spectroscopy was fed back through two proportion-integral-differential circuits to lock the 480 nm diode laser.A combined linewidth of about 1 MHz is achieved during the locking period.