Cr∶Nd∶GSGG晶体1.061 μm受激发射截面随温度变化特性研究

测量了Cr∶Nd∶GSGG晶体从 - 70℃到 +80℃温度下的荧光发射光谱和荧光寿命 ,计算了该晶体在不同温度下 1 .0 61 μm受激发射截面 ,获得在此温度变化范围内受激发射截面随温度的线性变化关系     

Cr：Nd：GSGG晶体1．061μm受激发射截面随温度变化特性研究

测量了Cr：Nd：GSGG晶体从-70℃到 80℃温度下的荧光发射光谱和荧光寿命，计算了该晶体在不同温度下1．061μm受激发射截面，获得在此温度变化范围内受激发射截面随温度的线性变化关系。     

LD泵浦Nd∶LuVO4/Cr4+∶YAG被动调Q激光器

采用大功率半导体激光器端面泵浦Nd∶LuVO4晶体，利用Cr4+∶YAG晶体作为可饱和吸收元件，实现了1.06 μm激光的被动调Q运转.在泵浦功率为19.1 W时，获得最高平均输出功率为4.58 W，脉冲宽度为84 ns，单脉冲能量为36.6 μJ以及峰值功率为436.2 W的激光脉冲.     

LD抽运Cr4+∶YAG高重复率被动调Q Nd∶YVO4激光器

采用Cr4+∶YAG晶体作为可饱和吸收体，实现连续激光二极管（LD）端面抽运的Nd∶YVO4激光器的高重复率被动调Q.在注入抽运功率为8.8 W时，得到重复频率23.8 kHz、平均功率1.21 W的调Q脉冲序列；每个脉冲能量为51 μJ、脉宽为25 ns、峰值功率达到2.03 kW.实验上研究了脉冲重复频率、平均输出功率、脉冲宽度、单脉冲能量与抽运功率、输出镜透过率的关系.实验结果表明，当抽运功率较大时，脉冲重复频率和输出平均功率随着抽运功率的增加而减小，对此进行了合理的理论解释.     

双棒串接Nd∶YAG激光器对称型谐振腔的分析

采用矩阵光学的方法对双棒串接Nd∶YAG激光器对称型谐振腔进行研究。结果表明:谐振腔内棒的位置直接影响腔的稳定范围和模体积;每一个热焦距f对应有两个稳定区间,当f<360mm时,值较小的稳定区间范围较宽;当f>360mm时,值较大的稳定区间范围较宽,在这两种情况下,均为值较大的稳定区间对应的模体积较大,而且模体积和输出功率随棒主平面与反射镜间距离的增大而增大。     

半导体激光泵浦的Nd∶YVO_4激光器的1．064μm高效率连续输出

报道了半导体激光端面泵浦的Ｎｄ∶ＹＶＯ４激光器获得线偏振的１．０６４μｍ激光高效率连续稳定输出。在半导体激光功率为１．５Ｗ时，获得连续输出功率为８３７ｍＷ的ＴＥＭ００模，激光器泵浦阈值功率为１４０ｍＷ，斜率效率达６１．５％，光－光转换效率达５６％，电－光转换效率达１５％。     

新型Nd3+∶Ca4GdO(BO3)3自倍频晶体Cr4+∶YAG被动调Q激光特性研究

采用氙灯抽运自倍频晶体Nd3 +∶Ca4GdO(BO3 ) 3 (简称Nd∶GdCOB) ,Cr4+∶YAG被动调Q ,实现了Nd∶GdCOB晶体被动调Q激光运转 ,测量了饱和吸收体Cr4+∶YAG不同小信号透过率下绿激光单脉冲的输出能量、脉冲宽度、重复率 ,给出了描述Nd∶GdCOB晶体调Q工作原理的耦合波方程组 ,数值求解了该方程组 ,所得的理论结果与实验值相符合     

激光二极管端面连续抽运的Cr4+∶Nd3+∶YAG微片激光器输出特性研究

报道了腔长为 1.1mm的激光二极管端面抽运的Cr4 +∶Nd3 +∶YAG自调Q微片激光器 ,连续抽运下获得了平均功率为 5～ 18mW、重复频率为 1～ 10kHz的稳定的调Q激光脉冲输出序列。并且对微片激光器的调Q输出激光的单脉冲特性参量、重复频率以及抽运阈值功率等进行了理论研究 ,计算结果和实验结果比较吻合。     

双棒串接Nd∶YAG激光器的稳区分析和实验研究

用传输矩阵法理论分析了在含热致双折射补偿和不含热致双折射补偿两种情况下,r偏振和Ф偏振对双棒串接激光器谐振腔稳区的影响.选用低掺杂浓度的Nd∶YAG棒,实验上用含90°石英旋光片的双棒对称平行平面短腔获得了最佳实验结果.1064nm激光最高输出功率达482.3W,对应光-光转换效率为40.2%.     

双棒串接Nd∶YAG激光器的稳区分析和实验研究

用传输矩阵法理论分析了在含热致双折射补偿和不含热致双折射补偿两种情况下,r偏振和偏振对双棒串接激光器谐振腔稳区的影响.选用低掺杂浓度的Nd∶YAG棒,实验上用含90°石英旋光片的双棒对称平行平面短腔获得了最佳实验结果.1 064 nm激光最高输出功率达482.3 W,对应光-光转换效率为40.2％.     

Cr,Mg:GSGG 晶体生长、光谱性能及Cr4+形成机理的研究

采用传统提拉法单晶生长技术成功生长出了Cr,Mg:GSGG晶体, 并对生长出的晶体样品进行了氧化气氛和还原气氛退火处理. 通过对比分析退火处理前后样品吸收光谱的变化, 推断出晶体中四面体配位Cr⁴⁺离子的形成机理为: 晶体生长和高温氧化气氛退火的过程中, 四价Cr⁴⁺离子首先在八面体格位上形成, 然后在热激发作用下与邻近四面体格位上的Ga³⁺离子发生置换反应, 从而形成一定浓度的四面体配位Cr⁴⁺离子. 实验结果还表明, 随着电荷补偿离子Mg²⁺离子浓度的增大, 更有利于提高四面体配位Cr⁴⁺离子的浓度.     

Systematic considerations for the patterning of photonic crystal devices by electron beam lithography

Photonic crystal devices with feature sizes of a few hundred nanometers are often fabricated by electron beam lithography. The proximity effect, stitching error and resist profiles have significant influence on the pattern quality, and therefore determine the optical properties of the devices. In this paper, detailed analyses and simple solutions to these problems are presented. The proximity effect is corrected by the introduction of a compensating dose. The influence of the stitching error is alleviated by replacing the original access waveguides with taper-added waveguides, and the taper parameters are also discussed to get the optimal choice. It is demonstrated experimentally that patterns exposed with different doses have almost the same edge-profiles in the resist for the same development time, and that optimized etching conditions can improve the wall angle of the holes in the substrate remarkably.     

LD抽运Nd:LuVO4微片激光器性能研究

报道了一类新型的LD端面抽运Nd:LuVO4微片激光器,讨论了在不同掺杂浓度,不同厚度和不同透过率下的激光性质,测定了在不同抽运功率下,微片最佳激光输出功率与LD抽运温度的关系.在2W抽运功率下获得923mW的1064nm激光输出,阈值为48mW,斜效率为52%.对微片制冷后斜效率提高到59%.     

Cr,Nd:YAG self-Q-switched laser with high efficiency output

The high efficient laser performance of self-Q-switched laser in the co-doped Cr⁴⁺,Nd³⁺:YAG microchip with 1.8 mm thickness was demonstrated. The slope efficiency is varied with the reflectivity of output coupler at 1064 nm, and the highest slope efficiency of 26% was obtained for 95% reflectivity of output coupler at 1064 nm. The pulse width, the single pulse energy and the pulse repetition rate for different reflectivity of the output couplers were measured, and the experimental results agree with the numerical calculations of the passively Q-switched rate equations. This can lead to develop the diode laser pumped monolithic self-Q-switched solid-state microchip lasers, especially for the intracavity frequency-doubled solid-state microchip lasers.     

Laser performance of monolithic Cr,Nd:YAG self-Q-switched laser

The self-Q-switched laser performance of monolithic Cr⁴⁺,Nd³⁺:YAG concave-planar resonator with 5-mm length was studied experimentally and theoretically. The slope efficiency is as high as 24% and pump threshold is as low as 64 mW. The pulse width, the single pulse energy and the pulse repetition rate of monolithic Cr,Nd:YAG self-Q-switched laser were measured as a function of absorbed pump power. With the increase of pump power, the pulse width decreases and the pulse energy and the pulse repetition rate increase. The average output power of 91 mW with pulse width of 7 ns at repletion rate of 35.5 kHz was obtained at the maximum absorbed pump power of 440 mW, the peak power is as high as 370 W. The theoretical prediction of pulse energy, pulse width and pulse repetition rate as a function of absorbed pump power based on rate equations is in a good agreement with our experimental data. This can lead to develop the diode laser-pumped monolithic self-Q-switched solid-state microchip lasers.     

Direct numerical simulation of quasi-three-level passive Q-switched laser

The Runge-Kutta method is used to solve numerically the rate equations of quasi-three-level passive Q-switched laser directly without any approximate treatment of these differential equations. The 946 nm self-Q-switched Cr,Nd:YAG laser is chosen for example to describe the details. The time-dependence of intra-cavity photon density is obtained and its detailed real-time changing process is reproduced in numerical solution. The curves of laser output parameters such as average output power, pulse width, repetition rate, pulse energy and peak power changing with different cavity conditions such as pump power, output coupler reflectivity, Cr,Nd:YAG crystal length, Nd³⁺ ion and Cr⁴⁺ ion concentrations are simulated according to direct numerical solution rather than analytical expressions. This direct numerical simulation method can be widely used to describe and optimize the quasi-three-level passive Q-switched laser theoretically.     

Effect of Nd concentration on the laser performance of a new laser crystal: Nd : NaY(WO4)2

We have measured the transmission and emission spectra of a new crystal, Nd : NaY(WO₄)₂ (Nd : NYW). Using a Ti : sapphire laser as the pump source, the laser performances of Nd : NYW crystals with different concentrations are compared for the first time. The Nd³⁺ concentrations used are 1, 2, 4 and 5 at%. Our investigation shows that 2 at% is the optimum concentration. When the incident pump power is 575 mW, the 1.06 μm output can reach 184 mW, corresponding to an optical-to-optical efficiency of 32%. We believe that our work is significant for the further research and actual application of this promising laser crystal.     

Nd:YSAG单晶的光谱和激光性能

用提拉法生长了(1.5 at.%)Nd~(3+):Y_3Sc_2Al_3O_(12)(YSAG)激光晶体,摇摆曲线表明晶体结晶质量优良.测量了该晶体的吸收和发光光谱,表明其适合成熟的808 nm激光二极管(LD)抽运,其~4F_(3/2)→~4I_(11/2)跃迁最强发射波长为1059 nm,发射截面为1.03×10~(-19)cm~2,同时其激光上能级寿命为253μs,表明Nd:YSAG具有和Nd:YAG相近的效率,但其激光上能级寿命比Nd:YAG长约20μs.以LD抽运2 mm×2 mm×6 mm Nd:YSAG激光棒,激光阈值为0.85 W,最高输出功率为1.1 W,激光斜效率为21.1%,光-光转化效率为18.3%.综合表明Nd:YSAG单晶作为激光性能优良的全固态激光材料,更适合全固态调Q激光输出.