Exploiting the two-dimensional magneto-optical trapping of $^{199}\mathrm{Hg}$ for a mercury optical lattice clock

Exploiting the two-dimensional magneto-optical trapping of ${}^{199}{Hg}$ for a mercury optical lattice clock

Changlei Guo, Valentin Cambier, James Calvert, Maxime Favier, Manuel Andia, Luigi de Sarlo, and Sébastien Bize

Phys. Rev. A 107, 033116 – Published 27 March 2023

Abstract

Two-dimensional magneto-optical trapping (2D-MOT) is an efficient tool for generating a high flux of precooled atoms. A 2D-MOT for mercury (Hg) is so far missing despite the potential of this atomic species in several areas. Here, we present the characterization of a 2D-MOT for Hg enabled by addressing the $^{1} S_{0}$ - $^{3} P_{1}$ laser cooling transition at 254 nm. The laser source based on an ytterbium-doped fiber amplifier has low-frequency noise and high reliability. Parameters affecting the efficiency of the 2D-MOT are studied, i.e., optical trapping power, push beam power, cooling laser frequency detuning, and magnetic-field gradient. When used with a Hg optical lattice clock, the 2D-MOT increases by a factor of 4.5, the rate of preparation of the atomic samples, yielding an improved clock short term stability of $6.4 \times 10^{- 16}$ at 1 s.

Received 4 July 2022
Revised 13 January 2023
Accepted 13 March 2023

DOI:https://doi.org/10.1103/PhysRevA.107.033116

Physics Subject Headings (PhySH)

Atomic, optical & lattice clocks

Atomic, Molecular & Optical

Authors & Affiliations

Changlei Guo , Valentin Cambier ^*, James Calvert , Maxime Favier, Manuel Andia , Luigi de Sarlo, and Sébastien Bize

LNE-SYRTE, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, 61 Avenue de l'Observatoire, 75014 Paris, France

^*Corresponding author: valentin.cambier@obspm.fr

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 107, Iss. 3 — March 2023

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Images

Figure 1
The apparatus with 2D-MOT and three-dimensional (3D)-MOT including a lattice cavity. The trapping beams (thick blue arrows) are labeled as 1, whereas the push beam (thin gray arrow) is labeled as 2. Other parts are also labeled and listed in the figure.
Reuse & Permissions
Figure 2
Schematic of the MOT laser subsystems. YDFA; SHG: second harmonic generation; UVC: UV cavity; AOM: acousto-optic modulator; PD: photodiode; AMP: amplifier; LPF: low-pass filter; VCO: voltage-controlled oscillator; $f / 8$ : frequency divider; F-V: frequency-to-voltage converter; PI: proportional-integral controller. The YDFAs and the subsequent SHG units are from commercial systems (Azurlight Systems). The UV lasers are generated in bow tie shape cavities by using $γ$ -barium borate (BBO) crystals. Part of the UV light from the first UV cavity (UVC1) is sent to a Hg cell for absolute frequency locking where the 3D-MOT detuning is controlled by AOM 1. Two seed lasers are locked with the help of a F-V converter (AD590, the input frequency is $\sim 350 kHz$ ). The 2D-MOT detuning is controlled by tuning the VCO frequency. The respective optical power of a seed laser, YDFA, and SHG is labeled.
Reuse & Permissions
Figure 3
(a) Relative intensity noise (RIN) at 254 nm in UVC 1 and UVC 2, respectively. (b) Frequency noises at 254 nm inferred from the error signal of the saturated absorption (S.A.) lock (green) from the detection noise of this lock (gray) and from the beat note between the two seed lasers (blue), respectively. The estimated noise of one UV laser (red dashed line) uses combined data from these curves and other information, such as servoloop bandwidths. The $β$ -separation line is used for laser linewidth estimation [26].
Reuse & Permissions
Figure 4
Characterization of the 2D-MOT. Atom number in the 3D-MOT measured with varying (a) 2D-MOT trapping power (push beam power is $0.8 %$ of the trapping power); (b) push beam power; (c) laser detuning in units of $γ$ (1.3 MHz); and (d) magnetic-field gradient. Only one parameter is changed in each curve. The 3D-MOT parameters are with 220-ms MOT duration time and 25.9-mW UV trapping power.
Reuse & Permissions
Figure 5
MOT-loading curves with different UV trapping powers in the 2D-MOT. The nominal trapping power for the 2D-MOT is $\sim 34.5$ mW. The 3D-MOT parameters are the same as the ones in Fig. 4.
Reuse & Permissions
Figure 6
Characterization of the Hg clock with the 2D-MOT. (a) A typical atomic spectroscopy signal measurement (transition probability, blue dots) using a Rabi- $π$ pulse with a length of 160 ms. The red solid line is a fit using a typical Rabi transition model. (b) Clock stability estimations. Gray squares: experimental data from dedrifted correction frequencies; black dots: experimental data from in-loop transition probabilities when running the clock; red solid line: data from the clock stability model.
Reuse & Permissions

Physical Review A

covering atomic, molecular, and optical physics and quantum information

Exploiting the two-dimensional magneto-optical trapping of ${}^{199}{Hg}$ for a mercury optical lattice clock

Changlei Guo, Valentin Cambier, James Calvert, Maxime Favier, Manuel Andia, Luigi de Sarlo, and Sébastien Bize

Phys. Rev. A 107, 033116 – Published 27 March 2023

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Physical Review A

covering atomic, molecular, and optical physics and quantum information

Exploiting the two-dimensional magneto-optical trapping of Hg199 for a mercury optical lattice clock

Changlei Guo, Valentin Cambier, James Calvert, Maxime Favier, Manuel Andia, Luigi de Sarlo, and Sébastien Bize

Phys. Rev. A 107, 033116 – Published 27 March 2023

Abstract

Physics Subject Headings (PhySH)

Authors & Affiliations

Article Text (Subscription Required)

References (Subscription Required)

Issue

Access Options

Authorization Required

Other Options

Download & Share

Images

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Log In

Search

Article Lookup

Paste a citation or DOI

Enter a citation

Exploiting the two-dimensional magneto-optical trapping of ${}^{199}{Hg}$ for a mercury optical lattice clock