發(fā)布時間：2018-05-17 16:14

  本文選題：溯源性 + 分辨率標定��； 參考：《北京化工大學》2015年碩士論文

【摘要】：激光回饋現(xiàn)象的物理內(nèi)涵極其豐富,亟待人們對它進行探索和發(fā)現(xiàn),基于此現(xiàn)象制作的激光回饋測量系統(tǒng)普遍具有靈敏度高、自準直的優(yōu)點。與傳統(tǒng)雙光路干涉儀相比,回饋干涉儀只需要一條光路即可完成信號探測和放大,因此它還具有結(jié)構(gòu)簡單緊湊、價格便宜等優(yōu)勢。目前,人們對激光回饋現(xiàn)象的研究更多地停留在弱回饋水平下,對強回饋水平下的研究少有涉獵,因為當處于強回饋水平時,激光器對外界信號的靈敏度很高,對干擾的抵抗能力較弱,信號檢測和處理的難度很大。針對上述優(yōu)勢和不足,本文對He-Ne激光器在較強回饋水平下的高階回饋現(xiàn)象及其在位移測量領域的應用做了較為系統(tǒng)的研究,提出了一種具有納米量級測量分辨率、可溯源至光波長的單重高階回饋位移測量系統(tǒng)及其標定方法。另外,為了提高系統(tǒng)的穩(wěn)定度,研制了針對回饋激光器的特殊穩(wěn)頻方法。首先,我們對單頻激光高階回饋現(xiàn)象作了系統(tǒng)的研究,得到了激光在非準直外腔下的高階回饋曲線。并運用軟件光線追跡和強弱回饋相互標定的方法,同時得到了外腔鏡在特定角度下所對應的激光回饋階次,成功獲得了系統(tǒng)具有納米量級的位移測量分辨率。在此基礎上,發(fā)現(xiàn)了在非準直外腔回饋下,激光腔內(nèi)的偏振跳變現(xiàn)象。為了利用這一現(xiàn)象進行位移判向,我們分別運用腔鏡加力和外腔旋轉(zhuǎn)波片的方式,成功控制了偏振跳變點在回饋條紋一個周期中的位置,并通過設定光強閾值的方法實現(xiàn)了位移判向。其次,我們通過在半外腔He-Ne激光器諧振腔內(nèi)加入石英晶體,并調(diào)整其角度的方法,在非準直外腔強回饋條件下,獲得了高密度、類余弦、相位差為90度的雙頻高階回饋位移測量曲線。系統(tǒng)位移測量分辨率同樣能達到納米量級,而且所得到的雙頻納米條紋可用于進一步的位移判向和電路條紋細分處理,最終獲得了亞納米量級的測量分辨率。再次,針對He-Ne激光高階回饋系統(tǒng)的特點,提出了結(jié)合激光管外電阻絲熱穩(wěn)頻和外腔鏡調(diào)制穩(wěn)頻的方法,成功解決了激光器在較強回饋水平時的穩(wěn)頻難題,提高了系統(tǒng)的抗干擾能力和測量準確度。最后,為了解決非準直凹面回饋外腔鏡上不同階次回饋光點相互混合,無法獲得準確的位移測量分辨率和幅值均勻的回饋條紋等問題,設計和搭建了基于Fabry-Perot回饋外腔的高階位移測量系統(tǒng)。并在這一系統(tǒng)中,首次獲得了幅值均勻、分辨率確定的單重高階弱回饋納米條紋。然后,我們運用傳統(tǒng)一階回饋半波長條紋與該納米條紋相互標定,通過微調(diào)F-P回饋鏡角度,獲得了與理論值相符合的兩種回饋條紋個數(shù)之比。該方法能幫助我們有效地減小因為光線傳播過程中離軸所造成的Abbe誤差,保證系統(tǒng)位移測量的溯源性。經(jīng)過標定,得到系統(tǒng)位移測量分辨率為0.55nm,其中可溯源的光學分辨率為10.9nm。該系統(tǒng)具有用作納米位移計量標準的潛力。
[Abstract]:The physical connotation of laser feedback phenomenon is extremely rich, it is urgent for people to explore and discover it. The laser feedback measurement system based on this phenomenon generally has the advantages of high sensitivity and self-collimation. Compared with the traditional dual optical path interferometer, the feedback interferometer needs only one optical path to detect and amplify the signal, so it also has the advantages of simple and compact structure, low price and so on. At present, the study of laser feedback is more focused on the weak feedback level, but less on the strong feedback level, because when the laser is at the strong feedback level, the laser is highly sensitive to the external signal. The ability to resist interference is weak, and it is very difficult to detect and process signals. In view of the above advantages and disadvantages, the high-order feedback phenomenon of He-Ne laser and its application in displacement measurement are systematically studied in this paper, and a kind of nanoscale measurement resolution is proposed. A single high order feedback displacement measurement system and its calibration method traceable to the wavelength of light. In addition, in order to improve the stability of the system, a special frequency stabilization method for feedback lasers is developed. Firstly, we systematically study the high-order feedback phenomenon of single-frequency laser, and obtain the high-order feedback curve of laser in non-collimated external cavity. By using the method of software ray tracing and strong or weak feedback mutual calibration, the laser feedback order corresponding to the external mirror at a specific angle is obtained, and the displacement measurement resolution of the system with nanometer magnitude is obtained successfully. On this basis, the phenomenon of polarization jump in the laser cavity is found under the non-collimation external cavity feedback. In order to make use of this phenomenon, we successfully control the position of polarization jump point in a period of feedback fringes by using the method of endoscope force and external cavity rotating wave plate, respectively. The method of setting the threshold of light intensity is used to determine the direction of displacement. Secondly, by adding quartz crystal into the resonator of semi-external cavity He-Ne laser and adjusting its angle, we obtain the high density and similar cosine under the condition of non-collimation external cavity strong feedback. A high order feedback displacement measurement curve with a phase difference of 90 degrees. The resolution of system displacement measurement can also reach nanometer order, and the obtained dual-frequency nanometer fringes can be used for further displacement direction determination and circuit fringes subdivision, and finally sub-nanoscale resolution can be obtained. Thirdly, according to the characteristics of He-Ne laser high-order feedback system, a method combining thermal frequency stabilization with external mirror modulation is proposed, which successfully solves the problem of laser frequency stabilization at strong feedback level. The anti-interference ability and measurement accuracy of the system are improved. Finally, in order to solve the problem that different order feedback light points are mixed with each other on the non-collimated concave feedback mirror, it is impossible to obtain accurate displacement measurement resolution and uniform amplitude feedback fringes, etc. A high order displacement measurement system based on Fabry-Perot feedback cavity is designed and built. In this system, the single-order high-order weak feedback nanoscale stripes with uniform amplitude and definite resolution are obtained for the first time. Then, we calibrate each other with the traditional first-order feedback half-wavelength fringe and the nanoscale fringe. By fine-tuning the angle of the F-P feedback mirror, we obtain the ratio of the number of the two feedback fringes in accordance with the theoretical values. This method can effectively reduce the Abbe error caused by off-axis in the process of ray propagation and ensure the traceability of the system displacement measurement. After calibration, the system displacement measurement resolution is 0.55 nm, and the traceable optical resolution is 10.9 nm. The system has the potential to be used as a nanometer displacement measurement standard.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN24

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本文編號：1902017