研究生: |
陳玠潾 |
---|---|
論文名稱: |
光激發原子磁量儀物理與應用研究 |
指導教授: |
楊鴻昌
Yang, Hong-Chang 洪姮娥 Horng, Herng-Er |
學位類別: |
碩士 Master |
系所名稱: |
光電工程研究所 Graduate Institute of Electro-Optical Engineering |
論文出版年: | 2011 |
畢業學年度: | 99 |
語文別: | 中文 |
論文頁數: | 46 |
中文關鍵詞: | 光激發原子磁量儀 |
論文種類: | 學術論文 |
相關次數: | 點閱:78 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 |
銜接學長的實驗並改良,目前已成功獲得磁共振訊號,並結合回饋控制電路測量外加磁場。
我們以795 nm圓偏振光入射銣元素圓柱形玻璃容器,其放置於一磁屏蔽環境,在此環境內以Helmholtz線圈產生均勻磁場,磁場方向與光前進方向相夾45度角,另外我們在與靜磁場垂直之方向,提供一射頻磁場使其產生共振效應,以光偵測器探測銣金屬蒸氣之磁共振效應,並以鎖相放大器測量與射頻磁場同相位及相位差九十度電壓訊號對頻率的關係圖,對同相位(in-phase)與九十度差相位(quadrature)之值依理論做曲線吻合,進而找出Rb85在B0=1984nT時,最佳工作狀態Brf為9.6 nT, 85P0=3×10-4,85Γ1=22 Hz,85Γ2=31 Hz。
接著我們製作回饋控制電路使得系統能測量外加磁場。鎖相放大器擷取一直流電壓輸出,訊號經積分器與加法器調整後,作為電壓控制振盪器之輸入,以產生特定頻率的交流訊號,交流訊號分別回饋給射頻磁場線圈產生新的共振頻率和鎖相放大器作為參考訊號。當系統有一微小磁場變動時,立即將訊號回饋給系統以達到新的共振穩態,透過獲取鎖相放大器電壓改變,得知瞬間磁場相對於初始磁場變動的大小。得知測量1.5 nT時,25 Hz以下能準確測量,結果取決於系統的反應時間和外加磁場大小需在Pip線性關係內。
[1] W. AndrÄa and H. Nowak eds., “Magnetism in Medicine,” Wiley-VCH, Berlin (1998).
[2] J. P. Wikswo, “Biomagnetic sources and their models”, in Proceedings of the Seventh International Conference on Biomagnetism, S. J. Williamson, M. Hoke, G. Stroink, and M. Kotani, eds., Plenum Press, New York-London, 1 (1998).
[3] D. Cohen, E. A. Edelsack, and J. E. Zimmerman, “Magnetocardiograms taken inside a shielded room with a superconducting point-contact magnetometer,” Appl. Phys. Lett., 16, 278 (1970).
[4] A. L. Bloom, “Principles of Operation of the Rubidium Vapor Magnetometer,” Appl. Opt., 1, 61 (1962).
[5] J.Dupont-Roc, S.haroche, and C.Cohen-Tannoudji, “Detection of very weak magnetic fields by 87Rb-zero-field level crossing resonances,” Phys. Lett., 28A, 638 (1969).
[6] E. B. Alexandrov and V. A. Bonch-Bruevich, “Optically pumped atomic magnetometers after 3 decades,” Opt. Eng., 31(4), 711 (1992).
[7] Bison G, Pasquarelli A, Weis A, Erné SN, ”SQUID vs. optically pumped magnetometer: a comparison of system performance.” Proceedings of the 14th International Conference on Biomagnetism; 2004 Aug 8-12; Boston, U.S.A. 2004B.
[8] W. E. 2Bell and A. L. Bloom, “Optical detection of magnetic resonance in alkali metal vapor,” Phys. Rev., 107 (6), 1559-1565 (1957).
[9] H. G. Dehmelt, “Modulation of a light beam by precessing absorbing atoms,” Phys. Rev., 105 (5), 1924 (1957).
[10] T. L. Skillman and P. L. Bender, “Measurement of the earth's magnetic field with a rubidium vapor magnetometer,” J. Geophys. Res., 63 (3), 513 (1958).
[11] E.Arimonodo, M.Inguscio, and P.Violino, "Experimental determinations of the hyperfine structure in the alkali aroms," Rev.Mod.Phys., 49, 31 (1997).
[12] J. C. Sltater, "Quantum Theory of Atomic Structure," McGraw-Hill, New York, (1960).
[13]Vanier J and Audoin C, ‘The Quantum Physics of Atomic Frequency Standards ,”(Bristol: IOP Publishing) 37, (1989).
[14] W. Happer, “Optical pumping,” Rev. Mod. Phys., 44(2), 169 (1972).
[15] H. G. DEIIXELT, “Paramagnetic Resonance Reorientation of Atoms and Ions Aligned by Electron Impact,” Phys. Rev., 103, 1125 (1956)
[16] S. Kanorsky, S. Lang, S. LÄucke, S. Ross, T. HÄansch, and A. Weis, “Millihertz magnetic resonance spectroscopy of Cs atoms in body-centered-cubic 4He,” Phys. Rev. A, 54, R1010 (1996).
[17] H. G. Dehmelt, “Slow spin relaxation of optically polarized sodium atoms,” Phys.Rev., 105 (5), 1487 (1957).
[18] A. Weis, J. Wurster, and S. I. Kanorsky, “Quantitative interpretation of the nonlinear Faraday effect as a Hanle effect of a light-induced birefringence,” J. Opt. Soc. Am. B, 10(4), 716 (1993).
[19] H. G. DEIIXELT, “Paramagnetic Resonance Reorientation of Atoms and Ions Aligned by Electron Impact,” Phys. Rev., 103, 1125 (1956)
[20] S. Kanorsky, S. Lang, S. LÄucke, S. Ross, T. HÄansch, and A. Weis, “Millihertz magnetic resonance spectroscopy of Cs atoms in body-centered-cubic 4He,” Phys. Rev. A, 54, R1010 (1996).
[21] Georg Bison, Robert Wynands, and Antoine Weis, “Optimization and performance of an optical cardio-magnetometer,” J. Opt. Soc. Am. B, 22, 77 (2005)
[22] Amar Andalkar, “Spontaneous Spin Polarization and Hysteresis in Cs Vapor Pumped by Linearly Polarizered Light,” Department of Physics, Washington University, (2001).
[23] G. Bison, R. Wynands, and A. Weis, "A laser-pumped magnetometer for the mapping of human cardiomagnetic fields," Appl. Phys. B, 76, 325 (2003).