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  本文選題：直接泵浦 + 固體拉曼激光器��； 參考：《哈爾濱工業(yè)大學》2015年碩士論文

【摘要】：全固體拉曼激光器是目前LD泵浦固體激光器及非線性光學領域的研究熱點。全固體拉曼激光器利用受激拉曼散射(Stimulated Raman Scattering,SRS)效應,結合不同波長的基頻光和不同拉曼頻移介質(zhì),可得到光譜范圍從紫外到近紅外的激光輸出。與其他非線性光學頻率變換技術相比,固體拉曼激光器具有無需相位匹配、脈寬窄、光束質(zhì)量好等優(yōu)點,并可用于實現(xiàn)1.5μm人眼安全波段的激光輸出。本文從理論及實驗兩方面,對880nm LD直接泵浦的1.5μm內(nèi)腔固體激光器進行了深入系統(tǒng)的研究。理論方面:利用非線性光學耦合波方程以及經(jīng)典諧振子模型,推導了穩(wěn)態(tài)和瞬態(tài)情況下斯托克斯散射光場的增益表達式,并結合實際測量參數(shù)理論計算了不同波長下增益系數(shù)大小。采用主動調(diào)Q拉曼激光器速率方程理論,結合四階龍格-庫塔法,數(shù)值模擬了反轉粒子數(shù)和腔內(nèi)光子數(shù)隨時間的變化情況,討論了拉曼激光脈沖的的建立和消減過程。根據(jù)矩陣光學理論,利用MATLAB軟件模擬計算了不同諧振腔結構下,基頻光光斑半徑和穩(wěn)定性因子隨腔長的變化以及腔內(nèi)不同位置處的光斑大小。模擬分析了不同泵浦水平下激光晶體以和拉曼晶體的熱透鏡效應及其對拉曼激光的影響。實驗方面:通過880nm LD直接泵浦方式端面抽運Nd:YVO4晶體,獲得了1342nm基頻光的有效振蕩,并利用YVO4晶體的一階Stokes效應,實現(xiàn)了從1342nm到1525nm的拉曼頻移激光輸出。采用三種不同腔型結構,研究了泵浦功率和脈沖重復頻率對1525nm拉曼激光的平均功率、脈沖寬度和波形、輸出光束質(zhì)量等參數(shù)的影響。在15.9W的LD泵浦功率及30k Hz的重復頻率下,最高獲得530m W的平均功率輸出。在脈沖重復頻率為10k Hz時,得到LD泵浦閾值的最低值為2.6W,并當LD泵浦功率大于9.1W時,1.5μm拉曼激光脈沖寬度穩(wěn)定在5ns左右,與基頻光脈沖相比,得到了有效壓縮。
[Abstract]:All-solid-state Raman lasers are currently the focus of LD pumped solid-state lasers and nonlinear optics. Using stimulated Raman scattering Raman scattering (SRS) effect, combined with different wavelength of fundamental frequency light and different Raman frequency shift medium, the laser output from ultraviolet to near infrared can be obtained by all-solid-state Raman laser. Compared with other nonlinear optical frequency conversion techniques, solid-state Raman lasers have the advantages of no phase matching, narrow pulse width and good beam quality, and can be used to achieve 1.5 渭 m human eye safe wavelength laser output. In this paper, a 1.5 渭 m intracavity solid-state laser pumped directly by 880nm LD is studied systematically and theoretically. Theoretically, the gain expressions of Stokes scattering light field under steady and transient conditions are derived by using nonlinear optical coupling wave equation and classical harmonic oscillator model. The gain coefficient at different wavelengths is calculated with the theory of actual measurement parameters. Based on the rate equation theory of active Q-switched Raman laser and the fourth-order Runge-Kutta method, the changes of the number of inversion particles and the number of photons in the cavity with time are numerically simulated, and the establishment and subtraction of Raman laser pulses are discussed. According to the theory of matrix optics, the variation of the radius and stability factor of the fundamental frequency light spot with the cavity length and the size of the spot at different positions within the cavity under different resonator structures are simulated by using MATLAB software. The thermal lens effect of laser crystal and Raman crystal and its influence on Raman laser are simulated and analyzed at different pumping levels. Experimental results show that ND: YVO4 crystal is pumped by 880nm LD directly, and the effective oscillation of 1342nm fundamental frequency light is obtained. The Raman frequency shift laser output from 1342nm to 1525nm is realized by using the first-order Stokes effect of YVO4 crystal. The effects of pump power and pulse repetition rate on the average power, pulse width, waveform and output beam quality of 1525nm Raman laser are studied by using three different cavity configurations. At a LD pump power of 15.9W and a repetition rate of 30kHz, the highest average power output of 530 MW is obtained. When the pulse repetition rate is 10 kHz, the lowest threshold of LD pump is 2.6 W, and the width of 1.5 渭 m Raman laser pulse is stable at 5ns when the LD pump power is greater than 9.1 W, and the effective compression is obtained compared with the fundamental frequency optical pulse.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN248

【參考文獻】

相關碩士學位論文 前2條

1 閆阿澤;腔內(nèi)泵浦的484nm納秒和頻激光器運轉特性研究[D];哈爾濱工業(yè)大學;2013年

2 高亮;脈沖1.1微米及連續(xù)1.5微米全固態(tài)拉曼激光器[D];山東大學;2014年

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本文編號：2049418