共查询到18条相似文献,搜索用时 187 毫秒
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以各向异性半解析热分析理论为基础,研究矩形横截面Nd∶YVO4激光晶体在有第三类热边界条件工作时,激光晶体温度场分布和晶体抽运面热形变分布.通过激光晶体工作特点分析,建立符合激光晶体工作状态的热模型.利用各向异性介质热传导方程的半解析求解方法,得出了矩形截面Nd∶YVO4晶体的温度场、端面热形变场的通解表达式.研究结果表明:当使用输出功率为15 W半导体激光器端面中心入射Nd∶YVO4晶体(晶体掺钕离子质量分数为0.5%)时,在抽运端面中心获得499.5 K最高温度和0.99 μm最大热形变量.和将第三类热边界条件近似为第二类热边界条件的通用做法相比更准确.这种方法可以应用到其它激光晶体热问题研究中,为有效解决激光系统热问题提供了理论依据. 相似文献
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第三类热边界条件对激光晶体热效应的影响 总被引:3,自引:2,他引:1
以各向异性半解析热分析理论为基础,研究矩形横截面Nd:YVO4激光晶体在有第三类热边界条件工作时,激光晶体温度场分布和晶体抽运面热形变分布.通过激光晶体工作特点分析,建立符合激光晶体工作状态的热模型.利用各向异性介质热传导方程的半解析求解方法,得出了矩形截面Nd:YVO4晶体的温度场、端面热形变场的通解表达式.研究结果表明:当使用输出功率为15 W半导体激光器端面中心入射Nd:YVO4晶体(晶体掺钕离子质量分数为0.5%)时,在抽运端面中心获得499.5 K最高温度和0.99 μm最大热形变量.和将第三类热边界条件近似为第二类热边界条件的通用做法相比更准确.这种方法可以应用到其它激光晶体热问题研究中,为有效解决激光系统热问题提供了理论依据. 相似文献
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高功率Nd∶YVO4/KTP腔内倍频晶体温度分布的半解析热分析 总被引:5,自引:1,他引:4
非线性晶体KTP采用Ⅱ类相位匹配腔内倍频时,不仅要求晶体满足基频光的偏振匹配条件,而且所选用的晶体要求符合λ/2波片的条件,才能使晶体的谐波转换效率达到最佳.由于倍频晶体吸收基频光能量引起晶体内部非均匀温升,改变晶体内部各点的折射率,也会使晶体产生不应有的热形变,破坏晶体初始的位相匹配条件,严重影响输出激光的品质和倍频效率.减弱、改善这种情况的关键是准确得出在实际工作条件下晶体内部温度场.利用半解析热分析方法得出了KTP晶体内部温度场的计算方法,分析了各种热参量变化对KTP晶体内部温度场的影响.得出的结果具有一定的普适性,可以应用到具有轴对称形式内热源的其它热模型温度场的计算分析中,对连续波腔内倍频激光系统的设计将起到指导作用. 相似文献
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非线性晶体KTP采用Ⅱ类相位匹配腔内倍频时,不仅要求晶体满足基频光的偏振匹配条件,而且所选用的晶体要求符合λ/2波片的条件,才能使晶体的谐波转换效率达到最佳。由于倍频晶体吸收基频光能量引起晶体内部非均匀温升,改变晶体内部各点的折射率,也会使晶体产生不应有的热形变,破坏晶体初始的位相匹配条件,严重影响输出激光的品质和倍频效率。减弱、改善这种情况的关键是准确得出在实际工作条件下晶体内部温度场。利用半解析热分析方法得出了KTP晶体内部温度场的计算方法,分析了各种热参量变化对KTP晶体内部温度场的影响。得出的结果具有一定的普适性,可以应用到具有轴对称形式内热源的其它热模型温度场的计算分析中,对连续波腔内倍频激光系统的设计将起到指导作用。 相似文献
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通过研究分析钨酸盐晶体Nd∶KY(WO4)2和Nd∶KG(WO4)2在室温下的吸收光谱,发现这2种晶体具有作为激光晶体的优良特性。根据Judd-Ofelt理论和测试所得的吸收光谱及数据,用VC++编程计算出晶体的谱线强度、振子强度、吸收截面等,拟合得Nd3+离子的3个晶场调节参数Ωλ(λ=2,4,6)的值,并从理论上计算了自发跃迁几率、能级寿命、荧光分支比和积分发射截面。从计算得出的荧光分支比β可以看出,Nd∶KY(WO4)2(β1060nm=0.4380)和Nd∶KG(WO4)2(β1060nm=0.4618)晶体荧光分支比都较大,计算了该晶体的X=Ω4/Ω6,并将其X值与其他晶体的X值加以比较,Nd∶KY(WO4)2和Nd∶KG(WO4)2均易于实现1.06μm激光输出,适合作为LD泵浦的钨酸盐晶体激光器。 相似文献
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《中国光学与应用光学文摘》2007,(1)
TN2442007010162YVO4-Nd∶YVO4复合晶体热效应研究=Thermal effect ofYVO4-Nd∶YVO4composite laser crystals[刊,中]/李隆(西安建筑科技大学理学院.陕西,西安(710055)),史彭…//光学精密工程.—2006,14(5).—786-791在全固态激光器中使用了复合结构的激光晶体,通过端面泵浦复合晶体工作特点分析,提出了矩形截面复合晶体热分析模型。在热模型中,考虑了复合晶体具有轴向加热、周边恒温,耦合后的泵浦光束具有高斯分布的特点,利用热传导方程,得出了YVO4-Nd∶YVO4复合晶体内部温度场及端面热形变的一般解析表达式。研究结果表明,在相… 相似文献
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非线性光学晶体CsLiB6O10谐波产生的允许参量分析 总被引:2,自引:2,他引:0
根据波耦合中的能量动量守恒和色散方程,数值模拟计算了CsLiB6O10晶体在II类相位匹配下的倍频和混频产生的允许参量理论曲线.通过与β-BaB2O4晶体的比较,得到了CsLiB6O10晶体的谐波具有走离角小、允许参量范围宽的结果. 相似文献
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Theoretical analysis and experimental research on thermal focal length of a YVO4/Nd:YVO4 composite crystal
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This paper investigates the temperature field distribution and thermal focal length within a laser diode array (LDA) end-pumped YVO4/Nd:YVO4 rectangular composite crystal. A general expression of the temperature field distribution within the Nd:YVO4 rectangular crystal was obtained by analysing the characteristics of the Nd:YVO4 crystal and solving the Poisson equation with boundary conditions. The temperature field distributions in the Nd:YVO4 rectangular crystal for the YVO4/Nd:YVO4 composite crystal and the Nd:YVO4 single crystal are researched respec- tively. Calculating the thermal focal length within the Nd:YVO4 rectangular crystal was done by an analysis of the additional optical path differences (OPD) caused by heat, which was very identical with experimental results in this paper. Research results show that the maximum relative temperature on the rear face of the Nd:YVO4 crystal in the composite crystal is 150 K and the thermal focal length is 35.7 mm when the output power of the LDA is 22 W. In the same circumstances, the experimental value of the thermal focal length is 37.4 mm. So the relative error between the theoretical analysis and the experimental result is only 4.5%. With the same conditions, the thermal focal length of the Nd:YVO4 single crystal is 18.5 mm. So the relative rate of the thermal focal length between the YVO4/Nd:YVO4 crystal and the Nd:YVO4 crystal is 93%. So, the thermal stability of the output power and the beam quality of the YVO4/Nd:YVO4 laser is more advantageous than the laser with Nd:YVO4 single crystal. 相似文献
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首先建立了无限大晶体截面近似下的时-空4维光场和温度场耦合的倍频模型. 并在瓦级功率激光抽运下,利用解析公式和迭代方法数值模拟了BBO晶体内的倍频过程.得到了基频光和倍频光的振幅和转换效率曲线以及温度场分布,展示了温度场及光场的时间演化过程. 其次分析了抽运功率和晶体长度对转换效率和温度场的影响. 结果给出,温度分布对转换效率和光束质量都有较大影响;对热效应引起的相位失配进行补偿能够很好地改善转换效率的下降,因此必须在实际应用中加以考虑.
关键词:
倍频
温度场
BBO晶体 相似文献
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A new method for the study of the distribution of the magnetic field in a superconducting sample is developed. The field profile in the interior of the sample is mapped from the data on the spin probe ESR-signal shift measured at different points over the plane surface. The main attention is focused to the penetration of a perpendicular magnetic field into single crystal strips. The penetration of magnetic flux into an YBCO crystal is shown to be delayed and this gives rise to formation of the steep fronts in the profile of the field near the center of the strip. The profile observed differs considerably from the well-known Bean picture. It is highly dependent on the magnetic history. For the case of a Bi:2212 rectangular crystal, the crossover of the magnetic field profile from a dome shape, typical for a geometrical barrier (T > 30 K), to a bulk pinning picture (T < 25 K) was observed upon variation of temperature. The analysis of the field distribution made it possible to determine the temperature dependence of the lower critical field. 相似文献
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In this paper, temperature distribution in the continuous and pulsed end-pumped Nd:YAG rod crystal is determined using nonclassical and classical heat conduction theories. In order to find the temperature distribution in crystal, heat transfer differential equations of crystal with consideration of boundary conditions are derived based on non-Fourier’s model and temperature distribution of the crystal is achieved by an analytical method. Then, by transferring non-Fourier differential equations to matrix equations, using finite element method, temperature and stress of every point of crystal are calculated in the time domain. According to the results, a comparison between classical and nonclassical theories is represented to investigate rupture power values. In continuous end pumping with equal input powers, non-Fourier theory predicts greater temperature and stress compared to Fourier theory. It also shows that with an increase in relaxation time, crystal rupture power decreases. Despite of these results, in single rectangular pulsed end-pumping condition, with an equal input power, Fourier theory indicates higher temperature and stress rather than non-Fourier theory. It is also observed that, when the relaxation time increases, maximum amounts of temperature and stress decrease. 相似文献
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An electro-optic tunable rectangular array illuminator in one-dimensional periodically poled LiNbO3 (PPLN) crystal is presented experimentally which result is in good agreement with results from simulation. The illuminator is formed based on the Talbot self-imaging effect by applying an electric field on PPLN. The intensity distribution of rectangular array could be precisely modulated. Compared with other array illuminators, this tunable illuminator uses a lower voltage and could get a more concentrated intensity distribution. The influence of the incident angle to the self-imaging patterns is studied for the first time. 相似文献
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The electric field distribution in Li Nb O3 crystal under different electrode shape is presented by using the digital holographic interferometry. Three configurations of phase modulator including the rectangular electrode type,single-triangle electrode type, and dual-triangle electrode type are performed in this experiment. The nonuniform electric field distribution in these phase modulators are observed and the electric field increases with voltage increasing. The digital holographic interferometry with high electro-optic effect improves the measurement precision. The digital holographic interferometry provides an effective way for studying the electric field distribution. Such in situ quantitative analysis of electric field distribution is a key to optimizing electrode shape. 相似文献