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Title: Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap

Abstract

We have realized adjustable multiple sub-Doppler traps (SDT's) in a six-beam magneto-optical trap (MOT) under asymmetric trap conditions. In the simplest case, one obtains an array of three SDT's, one usual trap at the origin and two additional traps symmetrically but oppositely located at equal and controllable distances from the origin, in good agreement with theoretical calculations. The easily adjustable array of SDT's readily available in the asymmetric MOT may open the possibility of novel atom optics or quantum optics experiments such as atom interferometer or quantum information.

Authors:
; ; ; ; ; ;  [1];  [2]
  1. Department of Physics and Astronomy, Seoul National University, Seoul 151-742, Korea (Korea, Republic of)
  2. Department of Physics and Institute of Opto-Electronic Science and Technology, Chonnam National University, Gwangju 500-757, Korea (Korea, Republic of)
Publication Date:
OSTI Identifier:
20982147
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.75.023409; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ASYMMETRY; ATOMS; BEAMS; INTERFEROMETERS; MAGNETO-OPTICAL EFFECTS; OPTICS; QUANTUM INFORMATION; TRAPS

Citation Formats

Heo, Myoung-sun, Kim, Kihwan, Lee, Ki-Hwan, Yum, Dahyun, Shin, Soyoung, Kim, Yonghee, Jhe, Wonho, and Noh, Heung-Ryoul. Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.023409.
Heo, Myoung-sun, Kim, Kihwan, Lee, Ki-Hwan, Yum, Dahyun, Shin, Soyoung, Kim, Yonghee, Jhe, Wonho, & Noh, Heung-Ryoul. Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap. United States. doi:10.1103/PHYSREVA.75.023409.
Heo, Myoung-sun, Kim, Kihwan, Lee, Ki-Hwan, Yum, Dahyun, Shin, Soyoung, Kim, Yonghee, Jhe, Wonho, and Noh, Heung-Ryoul. Thu . "Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap". United States. doi:10.1103/PHYSREVA.75.023409.
@article{osti_20982147,
title = {Adjustable multiple sub-Doppler traps in an asymmetric magneto-optical trap},
author = {Heo, Myoung-sun and Kim, Kihwan and Lee, Ki-Hwan and Yum, Dahyun and Shin, Soyoung and Kim, Yonghee and Jhe, Wonho and Noh, Heung-Ryoul},
abstractNote = {We have realized adjustable multiple sub-Doppler traps (SDT's) in a six-beam magneto-optical trap (MOT) under asymmetric trap conditions. In the simplest case, one obtains an array of three SDT's, one usual trap at the origin and two additional traps symmetrically but oppositely located at equal and controllable distances from the origin, in good agreement with theoretical calculations. The easily adjustable array of SDT's readily available in the asymmetric MOT may open the possibility of novel atom optics or quantum optics experiments such as atom interferometer or quantum information.},
doi = {10.1103/PHYSREVA.75.023409},
journal = {Physical Review. A},
number = 2,
volume = 75,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • We present a semiclassical theory of the sub-Doppler forces in an asymmetric magneto-optical trap where the trap-laser frequencies are unequal to one another. To solve the optical Bloch equations, which contain explicit time dependence, unlike in the symmetric case of equal laser detunings, we have developed a convenient and efficient method to calculate the atomic forces at various oscillating frequencies for each atomic density matrix element. In particular, the theory provides a qualitative understanding of the array of sub-Doppler traps (SDTs) recently observed in such an asymmetric trap. We find that the distances between SDTs are proportional to the relativemore » detuning differences, in good agreement with experimental results. The theory presented here can be applied to a dynamic system with multiple laser frequencies involved; the number of coupled equations to solve is much reduced and the resulting numerical calculation can be performed rather simply and efficiently.« less
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  • Magneto-optical traps (MOTs) of Er and Dy have recently been shown to exhibit populationwide sub-Doppler cooling due to their near degeneracy of excited- and ground-state Landeg factors. We discuss here an additional, unusual intra-MOT sub-Doppler cooling mechanism that appears when the total Dy MOT cooling laser intensity and magnetic quadrupole gradient increase beyond critical values. Specifically, anisotropically sub-Doppler-cooled cores appear, and their orientation with respect to the quadrupole axis flips at a critical ratio of the MOT laser intensity along the quadrupole axis versus that in the plane of symmetry. This phenomenon can be traced to a loss of themore » velocity-selective resonance at zero velocity in the cooling force along directions in which the atomic polarization is oriented by the quadrupole field. We present data characterizing this anisotropic laser cooling phenomenon and discuss a qualitative model for its origin based on the extraordinarily large Dy magnetic moment and Dy's near degenerate g factors.« less
  • We report experimental evidence of Sisyphus cooling in atoms with a {sup 1}S{sub 0} ground state. Since J=0, any cooling mechanism which requires multiple sublevels can only occur in the isotopes which have nuclear spin I{ne}0. Ytterbium has seven stable isotopes and offers a unique system in which we can study cooling on F=0{yields}1 ({sup 168,170,172,174,176}Yb), F=1/2{yields}3/2 ({sup 171}Yb), and F=5/2{yields}7/2 ({sup 173}Yb), depending on the selection of isotope. We have trapped each of the seven stable isotopes of ytterbium in a magneto-optical trap (MOT) using the strong {sup 1}S{sub 0}-{sup 1}P{sub 1} transition, and transferred them into a secondmore » MOT which uses the much narrower {sup 1}S{sub 0}-{sup 3}P{sub 1} intercombination transition. We have measured the temperature of isotopes {sup 171}Yb, {sup 173}Yb, and {sup 174}Yb in the {sup 1}S{sub 0}-{sup 3}P{sub 1} MOT, as a function of the intensity and detuning of the trapping laser. The temperature of {sup 174}Yb was found to increase more rapidly with intensity than predicted by Doppler cooling theory, in agreement with earlier work on alkaline-earth atoms. In the odd isotopes the temperature was found to decrease with increasing angular momentum, as observed in earlier experiments and three-dimensional simulations.« less
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