雷射鎖頻在原子分子結構研究、精密量測、光纖通訊與原子鐘等研究上是重要的課題，利用原子分子躍遷光譜可作為雷射鎖頻的依據，得到頻率精準的雷射光。

本實驗量測氦-四氣體躍遷波段位於1083 nm附近，對應躍遷譜線D1及D2線的偏振光譜譜線。利用擬合軟體Origin以高斯函數分析頻寬及譜線形狀，並以都普勒線寬公式算出該氣體分子團的溫度。

The laser frequency stability is an important topic in varies AMO research realms, such as molecule structures, optical-fiber communication, metrology, and the atomic clock. One of the trustable reference to facilitate frequency-locking is atomic spectroscopy.

We measured the polarization spectroscopy of gaseous helium-4, around the 1083-nm D1 and D2 transition lines. By using the Origin software, we fit the data with the Gaussian distribution function, analyzing the line-shape, and calculating the temperature of the gases by the Doppler broadening equation.

第1章 導論 ........................................................ 1
氫原子模型 ...................................................... 2
偏振光譜 ........................................................ 7
第2章 原理 ........................................................ 8
第3章 實驗 ....................................................... 14
利用He-4 氣體實現偏振光譜的微分譜線 ............................ 14
氦原子吸收光譜 ................................................. 17
氦原子飽和吸收光譜 ............................................. 19
第4章 結論與未來展望 ............................................. 21
參考書目 ......................................................... 22

1. Reece, J.B., Campbell Biology. 2011: Benjamin Cummings / Pearson.
2. Wu, T., et al., Observation and optimization of 4He atomic polarization spectroscopy. Optics Letters, 2013. 38(6): p. 986-988.
3. Wieman, C. and T.W. Hänsch, Doppler-Free Laser Polarization Spectroscopy. Physical Review Letters, 1976. 36(20): p. 1170-1173.
4. Carl Edwin Wieman, Polarization spectroscopy and the measurement of the lamb shift in the ground state of hydrogen / . Ann Arbor : University Microfilms International, 1977.
5. Pearman, C.P., et al., Polarization spectroscopy of a closed atomic transition: applications to laser frequency locking. Journal of Physics B: Atomic, Molecular and Optical Physics, 2002. 35(24): p. 5141.
6. Ohtsubo, N., T. Aoki, and Y. Torii, Buffer-gas-assisted polarization spectroscopy of Li6. Optics Letters, 2012. 37(14): p. 2865-2867.
7. Pahwa, K., L. Mudarikwa, and J. Goldwin, Polarization spectroscopy and magnetically-induced dichroism of the potassium D2 lines. Optics Express, 2012. 20(16): p. 17456-17466.
8. Thomsen, J.W., et al., Modulation-free frequency stabilization of a dye laser by polarization spectroscopy. Measurement Science and Technology, 1995. 6(2): p. 170.
9. Bohler, C.L. and B.I. Marton, Helium spectroscopy using an InGaAs laser diode. Optics Letters, 1994. 19(17): p. 1346-1348.
10. Okubo, S., K. Iwakuni, and T. Hasegawa, Modulation-free laser frequency stabilization to a saturated sub-Doppler spectral line in a transversal magnetic field. Optics Communications, 2012. 285(20): p. 4107-4111.
11. Demtröder, W., Laser Spectroscopy: Vol. 2: Experimental Techniques. 2008: Springer.
12. Preston, D.W., Doppler‐free saturated absorption: Laser spectroscopy. American Journal of Physics, 1996. 64(11): p. 1432-1436.