波長位移量測用干涉儀

Interferometer for Determining Wavelength Shift

鄭晏如(Yan-Ru Cheng)

指導教授 ： 林世聰

國立臺北科技大學/機電學院/光電工程系所/碩士(2006年)

https://doi.org/10.6841/NTUT.2006.00097

摘要

本文提出了兩個可以量測波長位移量之量測方法。實驗架構I係以二極體雷射(Laser Diode, LD)為光源，利用差頻干涉儀技術(Heterodyne Interferometer)產生外差光源，並將外差光源引入同時具有非等光程(unequal-path)以及共路徑(common-path)特色之干涉儀，量測參考訊號與量測訊號之間的相位變化，此相位變化為入射光波長的函數，故可得到入射光波長的微小位移量。實驗I的誤差主要來自於實驗架設中雷射光是否垂直入射於平板玻璃及溫度的變化，本文並針對此兩項誤差源，進行量測與探討，證實溫度所造成之實驗誤差遠大於因雷射光沒有正向入射於平板玻璃所造成之量測誤差，因此，如果可以加上良好的溫控系統，則可以再次提高本量測系統之解析度以及穩定度。實驗結果亦成功地驗證了本干涉儀同時具有1.1×10-10(lumda2/nm)的高解析度及0.001nm的高穩定度之優勢。
實驗ΙΙ係以二極體雷射(COHERENT VMB2.3-12 MVP LAB)為光源，實驗架構為亦具有非等光程及共路徑特色之干涉儀，並配合旋轉偏極板的機制得到參考訊號以及量測訊號兩週期性訊號。由於參考訊號與量測訊號之間相位變化為入射光波長的函數，故可有效獲得入射光波長的微小位移量。實驗ΙΙ的量測誤差來自於，若Savart晶體具有微小的傾斜角度，使得o光與光e光產生光程差的變化，而造成相位的變化；其次是光路中的1/4波板若未校正，會使相位有明顯的差異。最後，實驗結果驗證了本干涉儀同時具有2.2×10-10(lumda2/nm)的解析度及0.003nm的穩定度。

關鍵字

波長位移 ； 差頻干涉儀

並列摘要

Two interferometers with the characteristics of unequal- and common-path interferometers are proposed for wavelength shift determinations in this thesis. The first one delivers a heterodyne light source into the interferometer to out-put a reference beam and a test beam whose phase difference is extracted by a phase meter. A wavelength shift of the light source would drift phase difference and thus can be obtained if the variation of the phase difference is detected.
A setup constructed to accomplish the interferometer and its application in wavelength shift determination are introduced. The result of the wavelength shift determination agrees the validity and applicability of the interferometer. The resolution and stability of the setup were also examined and were 1.1×10-10(lumda2/nm) and0.001nm, respectively.
The second one is with a more compact optical structure. In which, a monodyne light source is split into a reference and a test beams, these two beams propagate through a quarter wave plate and a rotating analyzer to produce two signals whose phase difference is obtained by comparing these two signals in a phase meter. Experimental result from using the setup of this interferometer also agrees the validity and applicability of the interferometer. And the resolution and stability of the setup were examined, which were 2.2×10-10(lumda2/nm)and 0.003 nm, respectively.

並列關鍵字

wavelength shift ； heterodyne interferometer

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