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Experimental results are reported on the room-temperature operation of Nd:YAG lasers end pumped with an LED. The radiation from a 10-percent-efficient 0.46-mm-diam domed LED was coupled to the end of a 0.46-mm-diam × 5.0-mm-long laser rod with a large hemispherical reflector. At 20°C, a multimode laser power of 0.25 mW was obtained at an LED current of 250 mA. By measuring the variation of threshold pump power with rod temperature and the laser power versus pump power just above threshold, both the laser cavity loss and the output mirror transmission were determined. A round-trip cavity loss as low as 0.022 percent was measured. A calculation of the fractional pump power absorbed in the rod for the LED spectrum gave 56 percent for a 5-mm-long rod while measurements showed that 30 to 35 percent of the LED power was being absorbed indicating an LED-to-laser rod coupling efficiency of 54 to 63 percent for this arrangement. With such efficient absorption of pump power and low cavity loss, end-pumped Nd:YAG lasers with high slope efficiencies above threshold are possible. 相似文献
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Experimental results on the first miniature Nd:YAG laser end-pumped by a single incoherent infrared-emitting diode are given. Laser operation was verified by measurements of relaxation oscillations, angular divergence, wavelength, and nonlinear output. In order to emit in the 0.81- μm pump band of Nd:YAG, the GaAs1-x Px diode required cooling to 88 K (-185°C). Cooling the diode increased its efficiency while cooling the rod decreased the pump power necessary to reach threshold. With both laser mirrors highly reflecting at 1.06 μm, the maximum pulse powerP_{D}^{th} emitted by the diode at threshold was 6.2 ± 1.2 mW. The diode power required for laser threshold at room temperature was derived and compared with more recent experiments. Miniature size and long-lived solid-state components make this laser attractive for further development. 相似文献
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我们研制了一台二极管连续端泵浦的Nd:YAG激光器,用国产激光二极管作泵浦源,泵浦激光波长为0.808μm。激光介质为φ5×5mm的Nd:YAG棒,输出激光波长为1.06μm,用CCD相机和图象处理系统记录和分析激光光斑,得到激光横模为TEM00模,当输入谐振腔的泵浦功率为225mW时,输出连续激光功率最高达76.4mW,光-光转移效率为33.9%,电光斜效率达到9.1%,并做了腔外倍频实验。 相似文献
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为了计算二极管抽运Nd∶ YAG晶体温度场及热形变场,建立了端面绝热、周边恒温的晶体热模型.基于Nd∶ YAG晶体导热系数及热形变系数与其温度的函数关系,应用Newton切线法对热传导方程进行求解,得到了变导热系数和变热形变系数矩形截面Nd∶YAG晶体端面抽运下的温度场和热形变场的一般表达式,同时计算了Nd∶ YAG晶体在不同抽运功率和抽运光斑半径下内部温度场和热形变场的分布变化.结果表明,使用钕离子质量分数为0.01、尺寸为3mm×3mm×8mm的Nd∶ YAG晶体,在功率为60W、光斑半径为450μm的抽运光照射下,变导热系数的Nd∶ YAG晶体端面最大温升为55.7℃,最大热形变量为2.85μm,而按传统将Nd∶ YAG晶体导热系数、热形变系数均视为定值时,晶体端面最大温升为43.4℃,端面最大热形变为2.84μm. 相似文献
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The authors have experimentally measured the energy stored and the heat generated in flashlamp-pumped Cr:Nd:GSGG for three Cr3+ concentrations in the range of 1-2×1020 ions/cm3 . It has been found that the energy storage efficiency in these samples is 1.7 times greater than that of the Nd:YAG sample, and the normalized heating parameter χ, defined as the heat deposited per unit of stored energy, is 2.5 under the specified pumping conditions, with no evident dependence on the Cr3+ concentration. It has been been found that the measured χ value for the sample of Nd:YAG is 2.9 for the same pumping conditions. These observed χ values exceed expected values by factors of ~1.1 and 2 for the Cr:Nd:GSGG and Nd:YAG samples, respectively. The thermal focal length in the two materials was measured showing that the lensing is shorter in GSGG by a factor of 2.6 for the same available output power, or a factor of 4.5 for the same input pump power. The expected thermal lensing was determined using measured heat loads with no adjustable parameters, achieving satisfactory agreement with measured lensing values 相似文献
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为了准确研究LD端面抽运圆棒热容激光晶体Nd:YAG时产生的热效应,采用以半解析热分析理论为基础、结合弹性力学理论的研究方法,得出了圆棒热容激光晶体抽运阶段和冷却阶段的温度场、热应力场和端面形变量半解析计算方法。结果表明,当抽运总功率为200W,4阶超高斯LD对Nd:YAG抽运2s时,Nd:YAG圆棒热容激光晶体的端面最大应力为52.9MPa,低于晶体断裂阈值下线的50%;此时激光晶体端面形变为3.05μm。所得结果为优化热容激光器提供了理论支持。 相似文献
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A scalable diode-pumped Nd:YAG laser is described in which the gain element resembles a penta-prism. This design allows longitudinal pumping along five separate axes. Using five high-power single stripe laser diodes, 4.16 W of absorbed power produced 2.3 W CW at 1.06 μm. The slope efficiency was 56%, the output was plane polarized, and the laser operated in the TEM00 mode. The threshold power, was 48 mW. No evidence of thermal saturation was observed up to the maximum pump power. With an intracavity KTP crystal, 431 mW of CW amplitude-stable output at 532 nm was generated. Repetitive Q-switched operation is also reported 相似文献
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在腔长为 2 47mm的LD端面泵浦Nd :YAG激光器的谐振腔中加入一片凸透镜 ,改变腔型结构 ,发现输出功率由 0 .3 5W增至 1.19W ,M2 因子由 1.0 9增至 2 .6,阈值功率由 2 .78W降至 0 .68W ,与腔长为 2 0mm的谐振腔阈值功率相同。分析表明 ,由于透镜的变换作用 ,使得泵浦端面上振荡光斑与泵浦光斑的比例发生变化 ,在晶体后端面处泵浦光斑确定的情况下 ,激光器的输出功率和阈值功率主要取决于该处的振荡光斑大小 ,与有效模体积无直接关系 相似文献
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The focal length of the thermal lens and the beam quality factor (beam propagation factor) M2 for a multiple longitudinally diode pumped slab laser is deduced for pump and output powers up to 16 and 4.5 W, respectively. Due to the geometry of the arrangement, a stronger thermal lens is observed in the plane with the larger pump spot radius as predicted by an analytical model for slab geometries. In addition, the second stable zone of an asymmetric resonator is found to be advantageous for improved beam properties at high output powers 相似文献
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为了研究脉冲半导体激光器端面抽运激光晶体产生的热效应,对激光晶体瞬态温度场以及热形变场进行解析分析与计算。考虑到脉冲LD出射光具有超高斯分布,且Nd:YAG晶体热传导各向同性的特点,利用热传导Poission方程得到了超高斯分布脉冲LD端面抽运Nd:YAG晶体瞬态温度场以及热形变场的一般解析表达式,定量分析了单脉冲抽运过程中超高斯抽运光光斑半径及超高斯阶次、脉冲宽度对Nd:YAG晶体瞬态温场的影响以及准热平衡状态温度场的时变特性。结果表明,当脉冲LD端面抽运光具有3阶超高斯分布、抽运功率为80W、脉冲频率为100Hz、脉宽为200 s、钕离子掺杂质量分数为0.01的Nd:YAG晶体瞬态温度场随抽运脉冲呈现出周期性分布,准热平衡状态的温度在25.5℃到29.2℃之间成锯齿形周期分布;晶体抽运面的热形变量在0.13m和0.19m之间也呈现出周期性变化。该研究对于脉冲LD端面抽运全固态激光器热不敏谐振腔设计具有理论指导意义。 相似文献
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A long-pulse Cr:Nd:GSGG laser was operated at almost 2 J output energy and almost 5 percent efficiency, using an uncooled pump cavity. An Nd:YAG rod in the same pump cavity produced 3.75 percent efficiency. Using a water-cooled pump cavity of standard design, the thermal focusing of Cr:Nd:GSGG was found to be almost six times that of Nd:YAG for the same flashlamp input energy. The thermal birefringence of the GSGG was also observed to be significantly higher than that of YAG. The performance of aQ -switched Cr:Nd:GSGG laser was characterized and compared to the predictions of a mathematical model for the laser. This yielded an estimate of4.2 times 10^{-19} cm2for the peak stimulated emission cross section of Nd3+in GSGG. Using the same technique for Nd:YAG yielded a value of9 times 10^{-19} cm2. 相似文献
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通过对半导体激光端面入射复合晶体工作特点的分析,建立了符合实际工作情况的热模型,利用热传导方程求解方法,得出了圆形截面复合晶体的温度场分布和端面热形变场通解表达式.研究结果表明:当使用输出功率为1 8 W半导体激光器端面中心入射复合晶体YAG-Nd:YAG时,抽运端面中心获得91.21℃最高温升和2.53μm最大热形变量.复合晶体可以有效降低晶体中最高温升,但是不能减少晶体端面热形变. 相似文献
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光纤耦合LD端面抽运Nd:GdVO4晶体材料热效应分析 总被引:1,自引:3,他引:1
为了研究半导体激光器端面抽运激光晶体产生的热效应问题,采用解析分析的方法研究端面抽运激光晶体的温升以及热形变量的大小.通过激光晶体工作特点分析,考虑到Nd:GdVO_4晶体热传导各向异性的特点,采用各向异性传热的Poisson方程,得出了超高斯光束端面抽运Nd:GdVO_4晶体温度场以及热形变场的一般解析表达式.并定量分析了超高斯光束不同阶次、不同光斑尺寸抽运时对于Nd:GdVO_4晶体温度场以及热形变场的影响.结果表明,若半导体激光器的输出功率为30W,光学聚焦耦合器传输效率为85%,5阶超高斯光束沿中心端面抽运掺钕离子原子数分数为0.012的Nd:GdVO_4晶体,抽运面可获得419.3℃的最大温升,并产生0.711μm的热形变.该结果对估算Nd:GdVO_4晶体热焦距变化范围以及进行热不敏谐振腔设计具有理论指导作用. 相似文献