研究生: |
卓鴻文 Hung Wen Cho |
---|---|
論文名稱: |
銣87原子的玻色-愛因斯坦凝結及玻色凝結體中電磁引發透明效應之研究 Bose-Einstein Condensation of 87Rb Atoms and Study of Electromagnetically Induced Transparency in the Bose Condensate |
指導教授: |
余怡德
Ite A. Yu |
口試委員: | |
學位類別: |
博士 Doctor |
系所名稱: |
理學院 - 物理學系 Department of Physics |
論文出版年: | 2007 |
畢業學年度: | 96 |
語文別: | 英文 |
論文頁數: | 1冊 |
中文關鍵詞: | 玻色凝結體 、原子數量測 |
外文關鍵詞: | BEC, OP |
相關次數: | 點閱:3 下載:0 |
分享至: |
查詢本校圖書館目錄 查詢臺灣博碩士論文知識加值系統 勘誤回報 |
本論文將介紹銣87原子的玻色-愛因斯坦凝結體之實現過程,以直接又準確的方式量測凝結體中原子的數量,並且研究在玻色凝結體中電磁波引發透明的現象。
我們以雙磁光陷阱進行實驗,經過40秒的載入過程,可在第二個磁光陷阱中獲得 1.3×109 個低溫原子,再經過38秒的蒸發式降溫後,觀察到玻色-愛因斯坦凝結的現象,此時凝結體中原子數量為 6.2×104 個,相變溫度為 250 nK。
我們利用光抽運法準確地決定玻色凝結體中原子的數量,這個方法與光的頻率、強度和偏極都無關,只與被吸收的光子數有關,因此量測上造成的擾動也大大的減低,是一個可信度很高的量測方式,並且可以決定出只有幾千顆原子數的玻色凝結體。
我們再利用已實現的玻色凝結體來研究電磁波引發透明的現象。首先在低溫下進行電磁波引發透明的試驗,經由量測到的光譜中得到雙光子共振頻率,再利用既有的技術,在玻色凝結體中也得到一樣的結果。由於研究玻色凝結體的電磁波引發透明效應是經過一段自由擴散時間後所量測的,此時玻色凝結體的光學密度已降低至1左右,這條件對光存取實驗來講是不足夠的。下一階段,我們將利用光陷阱抓住玻色凝結體以保存凝結體的高光學密度特性,繼續進行電磁波引發透明和光存取的研究。
Bibliography
[1] H. C. Huse, ”Laser Cooling and Trapping Rubidium Atoms”. Master Thesis,
Department of Physics, National Tsing Hua University, Taiwan (1997)
[2] Mao Li-Fu, ”Development and Study of Dark Magneto-Optical Trap”. Master
Thesis, Department of Physics, National Tsing Hua University, Taiwan (1998)
[3] J. C. Lai, ”Development and Study of Polarization Gradient Cooling”. Master
Thesis, Department of Physics, National Tsing Hua University, Taiwan (1998)
[4] Hsu Chih-Luu, ”Development and Characterization of a Master-Oscillator-
Power-Ampification System for the Realization of Bose-Einstein Condensa-
tion”. Master Thesis, Department of Physics, National Tsing Hua University,
Taiwan (1999)
[5] Tung Shin-Kuang, ”Bose-Einstein Condensate of 87 Rb atoms”. Master Thesis,
Department of Physics, National Tsing Hua University, Taiwan (2001)
[6] Chien Hui-Chun, ”Evaporatively Cooling 87 Rb Atoms to Sub-μK”. Master
Thesis, Department of Physics, National Tsing Hua University, Taiwan (2004)
[7] A. Einstein, Sitzungsber. Kgl. Preuss. Akad. Wiss. 1924, 261 (1924); S. N.
Bose, Z. Phys. 26, 178 (1924)
[8] M. H. Anderson, J. R. Ensher, M. R. Matthews, C. E. Wieman, and E.
A. Cornell, ”Observation of Bose-Einstein Condensation in a Dilute Atomic
Vapor,” Science 269, 198 (1995)
[9] K. B. Davis, M.-O. Mewes, M. R. Andrews, N. J. van Druten, D. S. Durfee, D.
M. Kurn, and W. Ketterle, ”Bose-Einstein Condensation in a Gas of Sodium
Atoms,” Phys. Rev. Lett. 75, 3969 (1995)
70
[10] C. C. Bradley, C. A. Sackett, and R. G. Hulet, ”Bose-Einstein Condensation
of Lithium: Observation of Limited Condensate Number ,” Phys. Rev. Lett.
78, 985 (1997)
[11] E. L. Raab, M. Prentiss, Alex Cable, Steven Chu, and D. E. Pritchard, ”Trap-
ping of Neutral Sodium Atoms with Radiation Pressure,” Phys. Rev. Lett.
59, 2631 (1987)
[12] J. Ye, S. Swartz, P.Jungner, and J. Hall, ”Hyperfine structure and absolute
frequency of the 87 Rb 5P3/2 state,” Opt. Lett. 21, 1280 (1996)
[13] G. Barwood, P. Gill, and W. Rowley, ”Frequency measurements on optically
narrowed Rb-stabilised laser diodes at 780 nm and 795 nm,” Appl. Phys. B.
53, 142 (1991)
[14] S. Bize, Y. Sortais, M. S. Santors, C. Mandache, A. Clairon, and C. Salomon,
”High-accuracy measurement of the 87 Rb ground-state hyperfine splitting in
an atomic fountain,” Europhys. Lett. 45, 558 (1999)
[15] J. Vanier et al., The Quantum Physics of Atomic Frequency Standards, Adam
Hilger (1989)
[16] J. Dalibard and C. Cohen-Tannoudji, ”Laser cooling below the Doppler limit
by polarization gradients: simple theoretical models,” J. Opt. Soc.Am. B 6,
2023 (1989)
[17] H. F. Hess, ”Evaporative cooling of magnetically trapped and compressed
spin-polarized hydrogen,” Phys. Rev. B 34, 3476 (1986)
[18] C. J. Pethick and H. Smith, Bose-Einstein Condensation in Dilute Gases,
Chapter 3 and Chapter 4, Cambridge University Press (2002)
[19] Wolfgang Petrich, Michael H. Anderson, Jason R. Ensher, and Eric A. Cor-
nell, ”Stable, Tightly Confining Magnetic Trap for Evaporative Cooling of
Neutral Atoms,” Phys. Rev. Lett. 74, 3352 (1995)
[20] In a two-level system, the absorption cross section of a laser field is equal to the
imaginary part of ( 3λ
2
2π )
ρeg Γ
Ω , where ρeg is the amplitude of the density matrix
71
element between the excited state and the ground state. For the solution
of ρeg , see M. O. Scully and M. S. Zubairy, Quantum Optics (Cambridge
University Press, Cambridge, 1997), Sec. 5.3.2 and Eq. (17.1.20).
[21] J. F. O’Hanlon, ”A user’s guide to vacuum technology”, Wiley (1989)
[22] A. Roth, ”Vacuum technology”, North-Holland (1990)
[23] T. A. Delchar, ”Vacuum physics and techniques”, Chapman & Hall (1993)
[24] He Yan-Cheng, ”Study of the Stability of the Atom Number in Bose Conden-
sate”. Master Thesis, Department of Physics, National Tsing Hua University,
Taiwan (2007)
[25] Lee Yi-Chi, ”Study of the Transportation of Cold Atoms between the Dou-
ble Magneto-Optical Trap”. Master Thesis, Department of Physics, National
Tsing Hua Univeristy, Taiwan (2005)
[26] Tsai Zen-Hsiang, ”Effects of Elongation and Compression on the Magneto-
Optical Trap”. Master Thesis, Department of Physics, National Tsing Hua
University, Taiwan (2004)
[27] Liu Yu-Chen, ”Development of the magneto-optical trap using the MOPA
laser system”. Master Thesis, Department of Physics, National Tsing Hua
University, Taiwan (2004)
[28] Cheng Po-Wen, ”Quantum Storage of Single-Photon Pulses”. Master Thesis,
Department of Physics, National Tsing Hua Univeristy, Taiwan (2006)
[29] Y. C. Chen, Y. A. Liao, L. Hsu, and I. A. Yu, ”Simple technique for directly
and accurately measuring the number of atoms in a magneto-optical trap,”
Phys. Rev. A 64, 031401(R) (2001)
[30] Hung-Wen Cho, Yan-Cheng He, Thorsten Peters, Yi-Hsin Chen, Han-Chang
Chen, Sheng-Chiun Lin, and Ite A. Yu, ”Direct Measurement of the Atom
Number in a Bose Condensate,” Opt. Express 15, 12114 (2007)
72
[31] Chen Yong-Fan, ”Storage and Manipulation of Photonic Information with
Slow Light Effect”. PHD Thesis, Department of Physics, National Tsing Hua
Univeristy, Taiwan (2005)
[32] Y. F. Chen, Z. H. Tasi, Y. C. Liu, and I. A. Yu, ”Low-light-level photon
switching by quantum interference,” Opt. Lett. 30, 3207 (2005)
[33] Franco Dalfovo, Stefano Giorgini, Lev P. Pitaevskii, and Sandro Stringari,
”Theory of Bose-Einstein condensation in trapped gases,” Rev. Mod. Phys.
71, 463 (1999)
[34] C. J. Pethick and H. Smith, Bose-Einstein Condensation in Dilute Gases,
Chapter 6, Cambridge University Press (2002)
73