# Rydberg Interaction-Induced Distortion of the Autler–Townes Spectra in Cold Lithium Atoms

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## Abstract

**:**

## 1. Introduction

## 2. Experimental Setup and Methods

## 3. Results

## 4. Conclusions and Outlook

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## Abbreviations

AT | Autler–Townes |

BBR | Blackbody radiation |

EIT | Electromagnetically induced transparency |

FWHM | Full width at half maximum |

MOT | Magneto-optical trap |

RE | Rate equation |

UV | Ultraviolet |

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**Figure 1.**(

**a**) Relevant level scheme in ${}^{7}$Li. (

**b**) Excitation time sequence. Here r is the pulse repetition rate, ${\tau}_{\mathrm{ex}}$ is duration of the coupling and probe beams. The relative timings between pulses are not in scale.

**Figure 2.**Two-step $2{S}_{1/2}$–$2{P}_{1/2}$–$70S$ transition spectra for the low Rabi frequency (blue curve) and the high Rabi frequency (red curve) of the coupling beam. The dashed curve is the best fit by means of a Lorentzian distribution with full width at half maximum $\mathrm{FWHM}=10.8$ MHz; the black solid curve is the best fit by means of Equation (6) with the dephasing rate ${\gamma}_{3}=2\pi \times 43$ MHz and ${\Omega}_{\mathrm{c}}=2\pi \times 47$ MHz. The separation of AT peaks (the distance between two maximum values) is ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 34$ MHz, and the measured Rabi frequency determined from intensity of the coupling beam is ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 52\left(20\right)$ MHz.

**Figure 3.**Number of Rydberg atoms excited by application of single pulse with duration ${\tau}_{\mathrm{ex}}$ vs. probe beam detuning $\Delta $: (

**a**) ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 34$ MHz, ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 52$ MHz, ${\tau}_{\mathrm{ex}}=0.1$ $\mathsf{\mu}$s; (

**b**) ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 54$ MHz, ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 71$ MHz, ${\tau}_{\mathrm{ex}}=0.1$ $\mathsf{\mu}$s; (

**c**) ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 73$ MHz, ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 71$ MHz, ${\tau}_{\mathrm{ex}}=0.2$ $\mathsf{\mu}$s; (

**d**) ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 81$ MHz, ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 97$ MHz, ${\tau}_{\mathrm{ex}}=3$ $\mathsf{\mu}$s; (

**e**) ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}=2\pi \times 119$ MHz, ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}=2\pi \times 97$ MHz, ${\tau}_{\mathrm{ex}}=20$ $\mathsf{\mu}$s. The frequencies ${\Omega}_{\mathrm{c}}^{\mathrm{AT}}$ are determined by the separation of AT peaks. The measured Rabi frequencies ${\Omega}_{\mathrm{c}}^{\mathrm{exp}}$ are determined from intensity of the coupling beam.

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**MDPI and ACS Style**

Saakyan, S.; Morozov, N.; Sautenkov, V.; Zelener, B.B.
Rydberg Interaction-Induced Distortion of the Autler–Townes Spectra in Cold Lithium Atoms. *Atoms* **2023**, *11*, 73.
https://doi.org/10.3390/atoms11040073

**AMA Style**

Saakyan S, Morozov N, Sautenkov V, Zelener BB.
Rydberg Interaction-Induced Distortion of the Autler–Townes Spectra in Cold Lithium Atoms. *Atoms*. 2023; 11(4):73.
https://doi.org/10.3390/atoms11040073

**Chicago/Turabian Style**

Saakyan, Sergey, Nikita Morozov, Vladimir Sautenkov, and Boris B. Zelener.
2023. "Rydberg Interaction-Induced Distortion of the Autler–Townes Spectra in Cold Lithium Atoms" *Atoms* 11, no. 4: 73.
https://doi.org/10.3390/atoms11040073