Journal of East China Normal University(Natural Science) >
Numerical optimization of bichromatic adiabatic cooling
Received date: 2021-04-13
Online published: 2022-03-28
In recent years, a new laser cooling method—named bichromatic adiabatic cooling—has been developed; however, the method offers low cooling efficiency. In this paper, numerical optimization of the bichromatic adiabatic cooling process has been performed. It is shown that there is an optimal pulse time for the optical fields to achieve the highest cooling efficiency. Moreover, a comparison of the cooling efficiency with the Gaussian light pulse and square pulse shows that the cooling efficiency is insensitive to the pulse shape. Because this cooling method relies on adiabatic evolution of the light field-atom system, it is shown that it is better to slow the speed of the atomic beam to maintain the adiabatic condition. Finally, the effect of spontaneous emission on bichromatic adiabatic cooling is studied. The results show that use of a long pulse significantly reduces cooling efficiency.
Key words: bichromatic adiabatic cooling; cold atom; optical force
Chenyang QIAN , Guangjiong DONG . Numerical optimization of bichromatic adiabatic cooling[J]. Journal of East China Normal University(Natural Science), 2022 , 2022(2) : 127 -134 . DOI: 10.3969/j.issn.1000-5641.2022.02.015
1 | CHU S, HOLLBERG L, BJORKHOLM J E, et al. Three-dimensional viscous confinement and cooling of atoms by resonance radiation pressure. Physical Review Letters, 1985, 55 (1): 48- 51. |
2 | ASPET A, ARIMONDO E, KAISER R, et al. Laser cooling below the one-photon recoil energy by velocity-selective coherent population trapping[J], Physical Review Letters, 1988, 61(7): 826-829. |
3 | ANDERSON M H, ENSHER J R, MATHEWS M R, et al. Observation of Bose-Einstein condensation in a dilute atomic vapor [G]// Collected Papers of Carl Wieman. [S. l. ]: World Scientific Publishing Co Pte Ltd, 2008: 453-456. |
4 | ZHANG W Z, LIU W M. QED-based optical bloch equations without electric dipole-approximation: A model for a two-level atom interacting with a monochromatic X-ray laser beam [EB/OL]. (2012-09-04)[2021-03-01]. https://arxiv.org/abs/1206.3445. |
5 | LAWALL J, BARDOU F, SAUBAEM B, et al. Two-dimensional subrecoil laser cooling. Physical Review Letters, 1994, 73 (14): 1915- 1918. |
6 | S?DING J, GRIMM R, OVCHINNIKOV Y B, et al. Short-distance atomic beam deceleration with a stimulated light force. Physical Review Letters, 1997, 78 (8): 1420- 1423. |
7 | CORDER C, ARNOLD B, HUA X, et al. Laser cooling without spontaneous emission using the bichromatic force. Journal of the Optical Society of America B, 2015, 32 (5): B75- B83. |
8 | 李庆扬. 数值分析 [M]. 北京: 清华大学出版社有限公司, 2001. |
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