Basic Search / Detailed Display

Author: 陳玠潾
Thesis Title: 光激發原子磁量儀物理與應用研究
Advisor: 楊鴻昌
Yang, Hong-Chang
洪姮娥
Horng, Herng-Er
Degree: 碩士
Master
Department: 光電工程研究所
Graduate Institute of Electro-Optical Engineering
Thesis Publication Year: 2011
Academic Year: 99
Language: 中文
Number of pages: 46
Keywords (in Chinese): 光激發原子磁量儀
Thesis Type: Academic thesis/ dissertation
Reference times: Clicks: 93Downloads: 0
Share:
School Collection Retrieve National Library Collection Retrieve Error Report
  • 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。

    第一章 前言………………………………………………… 1 第二章 實驗原理…………………………………………… 2 2-1銣原子之結構及其特性……………………………… 2 2-1.1 銣原子之結構………………………………… 2 2-1.2銣原子與磁場交互作用之特性…………………4 2-2光學激發……………………………………………… 7 2-3純量光學激發磁量儀之工作原理…………………… 11 第三章 實驗架構……………………………………………16 3-1實驗系統總論…………………...……………………16 3-2電壓控制振盪器和射頻線圈電壓控制器……………20 3-3積分器和加法器……………………………………… 23 第四章 實驗方法與結果……………………………………25 4-1磁共振線形之fitting………………………………25 4-2量測外加磁場…………………………………………34 第五章 結論與未來展望……………………………………42 參考文獻………………………………………………………44

    [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).

    無法下載圖示 This full text is not authorized to be published.
    QR CODE