【摘要】：自從上世紀60年代第一臺激光器被發(fā)明以來,人們可以將強度很高、單色性很好的激光光束與物質相互作用,從而觀察到一系列前所未有的新奇現(xiàn)象,如光學整流、差頻、和頻、倍頻、混頻、受激拉曼散射、光束自聚焦等等,為了深入了解這些有趣的現(xiàn)象,非線性光學理論便應運而生了。 隨著非線性光學的研究日趨成熟,人們開始逐漸將已取得的研究成果廣泛應用到各個科技領域中,如利用光學非線性效應在光纖中產生光孤子、通過交叉相位和自相位調制制作全光開光、制造讀取速度更快,保真度更高的光存儲器件等等,這些應用在未來的量子計算與量子通信領域將產生巨大作用。基于非線性光學豐富并且重要的應用價值,越來越多的人們開始關注如何增強與調控激光與介質相互作用時的光學非線性效應。近年來人們逐漸將非線性光學的研究拓展至量子水平,比如在單光子條件和微腔中探究非線性增強的量子相干效應等等。 我們采用密度矩陣方法對N型四能級系統(tǒng)與三個光場的相互作用過程進行了數值模擬,計算中考慮了多普勒效應、碰撞增寬等多種實際效應的影響；并用綴飾態(tài)理論進行了分析和解釋。實驗上,自行搭建了光學腔系統(tǒng),通過腔透射譜的不對稱度獲得了N型四能級系統(tǒng)的自克爾非線性系數,并估算得到了該系數的絕對值。同時,測量了不同調節(jié)場強度下自克爾非線性系數隨探測場頻率的變化,所得結果和理論計算基本吻合。對兩者之間存在差異的原因我們也進行了較為合理的分析。本研究將為光孤子傳輸及基于自相位調制的部分應用提供新思路,從而更好地應用在光纖通信、全光開關等。
[Abstract]:Since the invention of the first laser in 1960s, people can interact with matter with high intensity and good monochromaticity, and a series of unprecedented novel phenomena, such as optical rectification, difference frequency, sum frequency, frequency doubling, mixing, stimulated Raman scattering, beam self-focusing and so on, have been observed. In order to deeply understand these interesting phenomena, nonlinear optical theory emerges as the times require. With the maturity of nonlinear optics, people begin to widely apply the existing research results to various scientific and technological fields, such as the generation of optical solitons in optical fiber by optical nonlinear effect, the fabrication of all-optical open light by cross-phase and self-phase modulation, the fabrication of optical memory devices with faster reading speed and higher fidelity, and so on. These applications will play a great role in the field of quantum computing and quantum communication in the future. Based on the rich and important application value of nonlinear optics, more and more people begin to pay attention to how to enhance and regulate the optical nonlinear effect of laser-dielectric interaction. In recent years, the study of nonlinear optics has been gradually extended to the quantum level, such as exploring the quantum coherence effect of nonlinear enhancement in single-photonic conditions and microcavities. In this paper, the interaction process between N-type four-level system and three light fields is simulated by density matrix method, and the effects of Doppler effect, collision broadening and other practical effects are taken into account in the calculation, and the affixed state theory is used to analyze and explain the interaction between N-type four-level system and three light fields. In the experiment, the optical cavity system is built, and the self-Kerr nonlinear coefficient of the N-type four-level system is obtained by the asymmetry of the cavity transmission spectrum, and the absolute value of the coefficient is estimated. At the same time, the variation of self-Kerr nonlinear coefficient with the frequency of detection field under different intensity of regulating field is measured, and the results are in good agreement with the theoretical calculation. We also make a reasonable analysis of the reasons for the differences between the two. This study will provide a new idea for optical soliton transmission and some applications based on self-phase modulation, so as to be better used in optical fiber communication, all-optical switch and so on.
【學位授予單位】：華東理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN248

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相關博士學位論文 前1條

1 李淑靜;多能級原子系統(tǒng)中量子相干增強的弱光非線性[D];山西大學;2008年

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