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Autoionization of Ultracold Cesium Rydberg Atom in 37D_{5/2} State

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## Abstract

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## 1. Introduction

## 2. Experimental Setup

## 3. Autoionization Mechanism Analysis

## 4. Results and Discussion

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 1.**(

**a**) Two-photon excitation diagram. The first photon, ${\mathrm{\Omega}}_{p}$, drives the lower transition, $|6{S}_{1/2},F=4\rangle $→$|6{P}_{3/2},{F}^{\prime}=5\rangle $, and its frequency is blue shifted ${\Delta}_{p}/2\pi $ = 360 MHz from the state $|6{P}_{3/2},{F}^{\prime}=5\rangle $ using a double-pass acousto-optic modulator (AOM). The second photon, ${\mathrm{\Omega}}_{c}$, couples the Rydberg transition $|6{P}_{3/2},{F}^{\prime}=5\rangle $→$|n{D}_{5/2}\rangle $. (

**b**) Sketch of an experimental setup. The coupling laser ${\lambda}_{c}$ = 510 nm and probe laser ${\lambda}_{p}$ = 852 nm are overlapped in the MOT center to excite ground atoms (small blue balls) to Rydberg states (large yellow balls). Free ions due to the autoionization are detected with the MCP detector and recorded with a computer. (

**c**) Experimental timing. After switching off MOT beams, the two-photon excitation lasers are turned on to excite cesium ground atoms to the Rydberg state. A ramped electric field is finally applied to ionize the Rydberg atoms after interaction time ${t}_{D}$ and drive free ions and Rydberg ions to the MCP detector.The rising time of the ramped field is 3 $\mathsf{\mu}$s, and the peak value is defined as ${E}_{ion}$.

**Figure 2.**Time of flight (TOF) of the two-photon spectroscopy for the laser excitation to $37{D}_{5/2}$ Rydberg state. The red upper line displays the TOF spectrum for the field ${E}_{ion}<{E}_{thres}$ (the baseline of the red curve is offset to discern the signals.) The black lower line represents the TOF spectrum for the field ${E}_{ion}>{E}_{thres}$. The ionization threshold value ${E}_{thres}$ of the $37{D}_{5/2}$ Rydberg state is 401.86 V/cm. The inset is an enlargement of the signals in the blue dashed area.

**Figure 3.**(

**a**) The calculated interaction potential of $37{D}_{5/2}$ pair for $\left|M\right|$ = 0–5, indicating that the interaction is anisotropic for different $\left|M\right|$, where M = ${m}_{j1}+{m}_{j2}$, ${m}_{j1}$ and ${m}_{j2}$ are the magnetic quantum numbers of atom 1 and 2, respectively. At the Rydberg atomic density of ∼${10}^{9}$ in this work, the interaction curves display repulsive potentials. (

**b**) Calculations of the BBR-induced decay rates of $37{D}_{5/2}$→${n}^{\prime}{P}_{3/2}$ transitions at T = 300 K. The transition of $37{D}_{5/2}$→$39{P}_{3/2}$ has the largest decay rate of ∼9000 s${}^{-1}$.

**Figure 4.**(

**a**) Measured TOF spectra of autoionization signals for laser excitation to $37{D}_{5/2}$ Rydberg state with the indicated delay time ${t}_{D}$ and the fixed Rydberg atomic density $\rho $ = 2.96$\phantom{\rule{3.33333pt}{0ex}}\times \phantom{\rule{3.33333pt}{0ex}}{10}^{9}$ cm${}^{-3}$. The cyan region marks the boxcar gate. The ramped field ${E}_{ion}\lesssim {E}_{thres}$. The zero point is the beginning of the ramped field. (

**b**) Measurements of the autoionization signals of $37{D}_{5/2}$ Rydberg state as the function of delay time ${t}_{D}$. The data display the average of 100 measurements at the two-photon resonance.

**Figure 5.**(

**a**) Measured ion signals as a function of ${t}_{D}$ for an indicated Rydberg atomic density. (

**b**) Measured autoionization signals at ${t}_{D}$ = 0 as a function of Rydberg atomic density.

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## Share and Cite

**MDPI and ACS Style**

Jiao, Y.; Hao, L.; Fan, J.; Bai, J.; Zhao, J.; Jia, S. Autoionization of Ultracold Cesium Rydberg Atom in 37*D*_{5/2} State. *Photonics* **2022**, *9*, 352.
https://doi.org/10.3390/photonics9050352

**AMA Style**

Jiao Y, Hao L, Fan J, Bai J, Zhao J, Jia S. Autoionization of Ultracold Cesium Rydberg Atom in 37*D*_{5/2} State. *Photonics*. 2022; 9(5):352.
https://doi.org/10.3390/photonics9050352

**Chicago/Turabian Style**

Jiao, Yuechun, Liping Hao, Jiabei Fan, Jingxu Bai, Jianming Zhao, and Suotang Jia. 2022. "Autoionization of Ultracold Cesium Rydberg Atom in 37*D*_{5/2} State" *Photonics* 9, no. 5: 352.
https://doi.org/10.3390/photonics9050352