Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optics Express

Accurate determination of the rotational constants of ultracold molecules using double photoassociation spectroscopy

Jie Ma, Yuqing Li, Wenliang Liu, Peng Chen, Guosheng Feng, Chenyang Hu, Jizhou Wu, Liantuan Xiao, Suotang Jia

Published Feb 10, 2014• 5 citations
Publisher

Abstract

We report on an accurate determination of the rotational constants of the ultracold long-range Cesium molecules in near dissociation domain. The scheme relies on a precise reference of the frequency difference in a double photoassociation spectroscopy induced by two laser beams based on an acoustic-optical modulator. The rotational constants are obtained by fitting a non-rigid rotor model into the frequency intervals of the neighboring rotational levels deduced from the reference.

DOI
10.1364/oe.22.003754

Related papers

Experimental Determination of the Rotational Constants of High-Lying Vibrational Levels of Ultracold Cs2 in the 0g– Purely Long-Range State

Jie Ma, Jizhou Wu, Gang Chen +6 more

We report on a quantitative experimental determination of the rotational constants for the high-lying vibrational levels of the ultracold pure long-range Cesium molecules formed via photoassociation. The scheme relies on a precise reference of frequency difference in a double photoassociation spectroscopy, which is induced by two laser beams based on an acoustic-optical modulator. The rotational constants are obtained by fitting a nonrigid rotor model into the frequency intervals of the neighboring rotational levels deduced from the reference.

The Journal of Physical Chemistry Letters•Oct 10, 2013•13 citations

Precise measurements of rotational constants of the pure long range state of ultracold cesium molecules

Jie Ma, Peng Chen, Wenliang Liu +5 more

The high resolution spectrum of ultracold Cs2 pure long range 0g- state is experimentally measured using modulated trap loss spectroscopic technology. Based on Double photoassociation spectroscopic technique, precise frequency difference reference signals are constructed to accurately calibrate the resonant frequency intervals of the ro-vibrational levels, thus obtaining the relationship between the frequency interval of rotational level and the rotational quantum number. The experimental data are fitted by the non-rigid rotational model, and the molecular rotational constants corresponding to different vibrational levels in the ultracold Cs2 pure long range 0g- state are acquired. The experimental results demonstrate a linear decrease of the rotational constant with the increase of vibrational quantum number, and the linear decreasing rate is -0.41m MHz0.01 MHz.

Acta Physica Sinica•Jan 1, 2013•2 citations

High sensitive determination of laser-induced frequency shifts of ultracold cesium molecules

Jizhou Wu, Zhonghua Ji, Yichi Zhang +5 more

We experimentally present a technique for sensitively determining the laser-induced frequency shifts of the long-range molecular vibrational and rotational levels. The scheme relies on an optical frequency shifter, leading to two laser beams with a precise and adjustable frequency interval. A series of photoassociation spectra are recorded with both beams inducing molecular lines, whose peak separation provides an accurate frequency ruler to measure the frequency shifts of cesium molecular levels, which have not yet been observed in previous reports. The data are compared to theoretical predictions and show a good agreement.

Optics Letters•May 24, 2011•21 citations

Direct measurement of the rotational constant of 0u+(6S1/2+6P1/2) long-range state via double-pass spectroscopy

Hu Chen-Yang, Wenliang Liu, Xu Run-Dong +4 more

In this paper, we obtain the rotational constant and the distortion constant of v=187 belonging to 0u+ state below the 6S1/2+6P1/2 disassociation limit. In our experiment, we first prepare the ultra-cold cesium sample in the MOT (magneto-optical trap) by six beams of pumping laser, one beam of repumping laser, and a pair of anti-Helmholtz coils. Then we construct a high-resolution frequency reference using the double-pass photoassociation technique. The double-pass photoassociation technique is a creative and robust method. We use a polarization beam splitter to split one laser beam from the laser to two beams-Laser Ⅰ and Laser Ⅱ; Laser Ⅱ then passes twice through an acousto-optic modulator (AOM) whose central frequency is 110 MHz, using a reflecting mirror and a convex lens before illuminating the MOT. We use two shutters-S1 and S2 to control Laser Ⅰ and Laser Ⅱ. Open S1 while keep S2 close to make Laser I interact with the MOT; and after the rotational spectroscopy of J=0-6 is observed, turn off S1 and turn on S2 immediately. Let laser II interact with MOT and obtain another part of spectroscopy that is exactly the same with J=6; we define this part of spectroscopy as J'=6. The frequency interval between J=6 and J'=6 is exactly 220 MHz for the scan process is strictly linear, and that can be an accurate frequency interval in our experiment. The laser intensities of these two laser beams have to be strictly equal in case of the laser-induced frequency shift. Using the frequency interval of 220 MHz, we can calculate the frequency interval of J=0-6. The detection method we used here is the trap loss spectroscopic technology by modulating fluorescence of cold atoms in the MOT, which allows a direct spectroscopy detection at the rovibrational levels for a very weak transition probability. With the frequency intervals of each rotational quantum number, we can fit the frequency intervals to the non-rigid model to derive the rotation constant B and distortion constant D which are crucial to precisely measure the full molecule potential curves as well as deepen our understanding of molecular formation. This kind of double-pass photoassociation technique not only can direct obtain the precise value of rotation constant B and distortion constant D as compared with the traditional photoassociation method, but also can obtain a relatively accurate potential energy curve. And another great advantage is that we are able to calculate the frequency intervals easily without the wavelength meter which is rather expensive and difficult to control.

Acta Physica Sinica•Jan 1, 2015•0 citations

High resolution photoassociation spectra of an ultracold Cs2long-range 0u+(6S1/2+ 6P1/2) state

Peng Chen, Yuqing Li, Yichi Zhang +4 more

In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to J = 7 are obtained. Three rovibrational levels of the long-range 0 u + state of Cs 2 below the (6S 1/2 + 6P 1/2 ) dissociation limit are specifically investigated. By fitting their binding energy intervals to the non-rigid rotational model, the rotational constant of the long-range 0 u + state is determined. A proportional dependence of the value of the rotational constant on the vibrational quantum number is demonstrated.

Chinese Physics B•Sep 1, 2013•5 citations

Photoassociation spectroscopy of ultracold Cs below the 6P1/2 limit

Marin Pichler, Hongmin Chen, William C. Stwalley

We have performed high precision photoassociation spectroscopy of ultracold cesium gas. Using trap-loss fluorescence detection and controlling the background cesium pressure we were able to photoassociate atoms into excited states of ultracold molecules with large detunings up to 56 cm(-1) below the Cs(6S(1/2)) + Cs(6P(1/2)) atomic asymptote. Vibrational progressions are assigned to 0(g)(-), 0(u)(+), and 1(g) long-range states. By fitting the spectral data to the LeRoy-Bernstein expression, the effective coefficients of the leading long-range interactions and the vibrational quantum number at dissociation are obtained. In addition we have observed spectral perturbations between states of the same symmetry belonging to different asymptotes (6P(1/2) and 6P(3/2)). The perturbations are manifested through irregular vibrational level spacings and are especially pronounced in the 0(u)(+) symmetry. Many observed rotational levels indicate d- and higher partial wave contributions to the photoassociation cross section in the presence of trapping laser light, while spectral regions with only weak features suggest nodes in the lower state wave functions corresponding to the two ground state atoms asymptote.

The Journal of Chemical Physics•Jul 8, 2004•30 citations
We report on an accurate determination of the rotational constants of the ultracold long-range Cesium molecules in near dissociation domain. The scheme relies on a precise reference of the frequency difference in a double photoassociation spectroscopy induced by two laser beams based on an acoustic-optical modulator. The rotational constants are obtained by fitting a non-rigid rotor model into the frequency intervals of the neighboring rotational levels deduced from the reference.
We report on a quantitative experimental determination of the rotational constants for the high-lying vibrational levels of the ultracold pure long-range Cesium molecules formed via photoassociation. The scheme relies on a precise reference of frequency difference in a double photoassociation spectroscopy, which is induced by two laser beams based on an acoustic-optical modulator. The rotational constants are obtained by fitting a nonrigid rotor model into the frequency intervals of the neighboring rotational levels deduced from the reference.
The high resolution spectrum of ultracold Cs2 pure long range 0g- state is experimentally measured using modulated trap loss spectroscopic technology. Based on Double photoassociation spectroscopic technique, precise frequency difference reference signals are constructed to accurately calibrate the resonant frequency intervals of the ro-vibrational levels, thus obtaining the relationship between the frequency interval of rotational level and the rotational quantum number. The experimental data are fitted by the non-rigid rotational model, and the molecular rotational constants corresponding to different vibrational levels in the ultracold Cs2 pure long range 0g- state are acquired. The experimental results demonstrate a linear decrease of the rotational constant with the increase of vibrational quantum number, and the linear decreasing rate is -0.41m MHz0.01 MHz.
We experimentally present a technique for sensitively determining the laser-induced frequency shifts of the long-range molecular vibrational and rotational levels. The scheme relies on an optical frequency shifter, leading to two laser beams with a precise and adjustable frequency interval. A series of photoassociation spectra are recorded with both beams inducing molecular lines, whose peak separation provides an accurate frequency ruler to measure the frequency shifts of cesium molecular levels, which have not yet been observed in previous reports. The data are compared to theoretical predictions and show a good agreement.
In this paper, we obtain the rotational constant and the distortion constant of v=187 belonging to 0u+ state below the 6S1/2+6P1/2 disassociation limit. In our experiment, we first prepare the ultra-cold cesium sample in the MOT (magneto-optical trap) by six beams of pumping laser, one beam of repumping laser, and a pair of anti-Helmholtz coils. Then we construct a high-resolution frequency reference using the double-pass photoassociation technique. The double-pass photoassociation technique is a creative and robust method. We use a polarization beam splitter to split one laser beam from the laser to two beams-Laser Ⅰ and Laser Ⅱ; Laser Ⅱ then passes twice through an acousto-optic modulator (AOM) whose central frequency is 110 MHz, using a reflecting mirror and a convex lens before illuminating the MOT. We use two shutters-S1 and S2 to control Laser Ⅰ and Laser Ⅱ. Open S1 while keep S2 close to make Laser I interact with the MOT; and after the rotational spectroscopy of J=0-6 is observed, turn off S1 and turn on S2 immediately. Let laser II interact with MOT and obtain another part of spectroscopy that is exactly the same with J=6; we define this part of spectroscopy as J'=6. The frequency interval between J=6 and J'=6 is exactly 220 MHz for the scan process is strictly linear, and that can be an accurate frequency interval in our experiment. The laser intensities of these two laser beams have to be strictly equal in case of the laser-induced frequency shift. Using the frequency interval of 220 MHz, we can calculate the frequency interval of J=0-6. The detection method we used here is the trap loss spectroscopic technology by modulating fluorescence of cold atoms in the MOT, which allows a direct spectroscopy detection at the rovibrational levels for a very weak transition probability. With the frequency intervals of each rotational quantum number, we can fit the frequency intervals to the non-rigid model to derive the rotation constant B and distortion constant D which are crucial to precisely measure the full molecule potential curves as well as deepen our understanding of molecular formation. This kind of double-pass photoassociation technique not only can direct obtain the precise value of rotation constant B and distortion constant D as compared with the traditional photoassociation method, but also can obtain a relatively accurate potential energy curve. And another great advantage is that we are able to calculate the frequency intervals easily without the wavelength meter which is rather expensive and difficult to control.
In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to J = 7 are obtained. Three rovibrational levels of the long-range 0 u + state of Cs 2 below the (6S 1/2 + 6P 1/2 ) dissociation limit are specifically investigated. By fitting their binding energy intervals to the non-rigid rotational model, the rotational constant of the long-range 0 u + state is determined. A proportional dependence of the value of the rotational constant on the vibrational quantum number is demonstrated.
We have performed high precision photoassociation spectroscopy of ultracold cesium gas. Using trap-loss fluorescence detection and controlling the background cesium pressure we were able to photoassociate atoms into excited states of ultracold molecules with large detunings up to 56 cm(-1) below the Cs(6S(1/2)) + Cs(6P(1/2)) atomic asymptote. Vibrational progressions are assigned to 0(g)(-), 0(u)(+), and 1(g) long-range states. By fitting the spectral data to the LeRoy-Bernstein expression, the effective coefficients of the leading long-range interactions and the vibrational quantum number at dissociation are obtained. In addition we have observed spectral perturbations between states of the same symmetry belonging to different asymptotes (6P(1/2) and 6P(3/2)). The perturbations are manifested through irregular vibrational level spacings and are especially pronounced in the 0(u)(+) symmetry. Many observed rotational levels indicate d- and higher partial wave contributions to the photoassociation cross section in the presence of trapping laser light, while spectral regions with only weak features suggest nodes in the lower state wave functions corresponding to the two ground state atoms asymptote.