高分子基体的固体染料激光器的制备和研究

制备了用于固体染料激光器的高分子共聚物基体 ,研究了两种激光染料 Rhodamine- B(Rh-B)和 Pyrromethene597(PM- 597)在高分子基质中的光谱性质。以调 Q的 Nd:YAG激光器的倍频光为抽运光源 ,在无外加谐振腔的条件下 Rh- B和 PM- 597掺杂的高分子基体中获得了高转换效率和大能量激光输出 ,可为固体染料激光器的实用化提供关键工作物质     

LD 脉冲泵浦被动调Q 窄脉冲大能量全固态激光器

利用Nd:YAG/Cr4+:YAG 键合微片激光晶体研制了被动调Q 大能量窄脉冲的全固态激光器,激光器采用脉冲激光二极管泵浦方式,设计了本振级和两级放大结构,分析了激光器系统的自激振荡和其抑制方法,在激光器本振级获得稳定脉冲激光输出的基础上,当两级放大器泵浦电流分别为83A 和85 A 时,获得了最大单脉冲输出能量为120 mJ,脉冲宽度为1.28 ns 的1 064 nm 激光输出,激光通过倍频后可得到65 mJ 的532 nm 绿光输出,其窄脉宽和高光束质量特性可为飞秒激光器啁啾放大提供良好的泵浦源。     

基于石墨烯被动调Q Nd:YAG晶体微片激光器

设计了以石墨烯作为可饱和吸收体的被动调Q掺钕钇铝石榴石晶体(Nd:YAG)微片激光器。该激光器采用三明治结构,附有石墨烯薄层的YAG晶体紧密压贴于工作物质Nd:YAG晶体上,晶体端面镀膜作为端面镜构成平行平面谐振腔。采用光纤耦合输出激光二极管端面抽运技术,利用石墨烯的可饱和吸收作用,在注入功率为1.17 W时实现微片激光器的调Q运转,获得波长1064.6 nm,重复频率300~807 kHz可调,最小脉冲宽度75 ns的激光输出。激光器最大输出功率38.4 mW,最大单脉冲能量54.7 nJ。     

2.94um Er:YAG电光调Q激光器及应用研究

随着2.94 激光在医学中的应用日益广泛,控制工作激光参数提高医疗安全性能显得尤为重要,因此对工作的激光进行调Q是很有必要的。文中介绍了利用双布儒斯特角切割的LiNbO3晶体作为电光Q开关的Er:YAG调Q激光器,在工作频率5Hz,脉冲泵浦能量92J条件下,获得了脉宽103 ~110ns,能量达到87mJ的调Q脉冲激光输出。并分别在静态和调Q模式下对龋牙进行了窝洞制样,利用扫描电子显微镜对样本扫描,对比显示调Q激光制样的效果更好。     

二极管抽运200Hz TEM00模Q开关Nd:YAG激光器

用三只QCW-600W激光二极管侧面抽运Nd:YAG激光器,在重复频率为200Hz,单脉冲注入能量为270mJ条件下,实现了29.7mJ,TEM00模调Q激光输出,M2=1.12,脉宽6.4ns,光-光转换效率11%,斜效率16.5%,输出能量不稳定度1.14%.通过KTP晶体腔外倍频,获得了单脉冲能量16.8mJ,脉宽5.6ns的绿光输出,倍频效率56.6%.     

1 532 nm全光纤Er/Yb共掺杂激光器

近年来,相干探测激光雷达是测量远距离低空风切变的有效手段,1.6 μm波段固体激光器以其人眼安全、探测器件成熟等优势成为相干雷达主要光源。其增益介质Er:YAG晶体在1532 nm波段有较强的吸收峰,但吸收谱较窄,因此通过使用1 532 nm光纤激光器进行谐振泵浦可以有效提高晶体输出效率。为此,文中以Er/Yb双包层光纤为增益介质,1532 nm光纤光栅为反射腔镜,976 nm半导体激光器为泵浦源,实现了全光纤化1532 nm激光输出。输出激光最大功率73.44 W,波长可调谐范围为1531.35~1532.14 nm,波长谱宽为0.06 nm,x和y方向的光束质量M2分别为1.38和1.26,是1.6 μm固体激光器的理想泵浦源。并采用此激光器泵浦Er:YAG非平面环形腔获得1.3 W单频激光输出,斜率效率为31.76%。     

基于石墨烯被动调Q Nd∶YAG晶体微片激光器

设计了以石墨烯作为可饱和吸收体的被动调Q掺钕钇铝石榴石晶体(Nd∶YAG)微片激光器。该激光器采用三明治结构,附有石墨烯薄层的YAG晶体紧密压贴于工作物质Nd∶YAG晶体上,晶体端面镀膜作为端面镜构成平行平面谐振腔。采用光纤耦合输出激光二极管端面抽运技术,利用石墨烯的可饱和吸收作用,在注入功率为1.17W时实现微片激光器的调Q运转,获得波长1064.6nm,重复频率300～807kHz可调,最小脉冲宽度75ns的激光输出。激光器最大输出功率38.4mW,最大单脉冲能量54.7nJ。     

LD脉冲抽运的被动调Q Nd:YVO4激光器的研究

报道在LD脉冲抽运的Nd：YVO4激光器中插入Cr^4＋：YAG,获得稳定的调Q激光输出。在输出镜透过率T=10％时,插入Cr^4＋：YAG的调Q阈值为19．1mJ,在抽运能量为34mJ时,测得脉冲宽度为38ns,输出能量为0．34mJ。实验研究了脉冲宽度随抽运能量的变化,并比较了不同透过率输出镜条件下Cr^4＋：YAG调Q的输出能量和调Q效率随抽运能量的关系。实验还把Cr^4＋：YAG换成BDN染料片,获得了比Cr^4＋：YAG调Q还窄的10ns左右的脉冲,并根据Cr^4＋：YAG和BDN染料片的调Q机理对一些实验现象作出合理的解释。     

室温脉冲Fe2+:ZnSe中红外激光特性研究

处于3~5m波段的激光源在遥感、环境保护、医疗、通信和红外对抗等民用和军用领域都有广阔的应用前景。Fe2+:ZnSe晶体由于在材料特性和光学特性等方面都具有明显优势,是3~5m波段极具潜力的激光介质之一。在室温条件下利用自制非链式脉冲HF激光器作为泵浦光源,对晶体直径为10 mm,厚度1 mm,Fe2+离子掺杂浓度为31019/cm3的Fe2+:ZnSe晶体进行了研究,获得了中心波长4 295 nm、最大输出能量78.8 mJ的中红外激光输出。输出激光能量相对于晶体吸收泵浦能量的转换效率为27.7%,斜率效率达28.8%。采用小角度（3）斜入射的方案很好地解决了Fe2+:ZnSe激光器谐振腔镜镀膜问题。     

High-performance integrated erbium/sup +3/-ytterbium/sup +3/ codoped glass waveguide laser

We report the design and characterization of an efficient erbium/sup +3/-ytterbium/sup +3/ codoped ion exchanged glass distributed Bragg reflector (DBR) laser pumped by a 980-nm pigtailed laser source. Laser oscillation at 1536 nm is demonstrated with a pump threshold of 35 mW and a slope efficiency of 10.6%. The dependence of lasing performance on pump wavelength detuning is examined for different cavity designs.     

双侧面90°抽运微通道致冷Yb:YAG板条激光器

报道了采用带有微柱镜的激光二极管阵列(LDA)双侧面90°排布抽运的Yb∶YAG板条激光器,实验中使用的激光晶体尺寸为6 mm×10 mm×1 mm,掺杂原子数分数为3%。抽运光通过自行设计的聚光系统聚焦成10 mm×1 mm的光斑进行抽运,聚光系统的效率为75%,晶体表面功率密度达到1.9 kW/cm2,晶体内抽运光交叠区的体功率密度达到38 kW/cm3,远高于阈值的1.7 kW/cm3。当激光器采用平-凹腔结构,耦合输出为6%时激光单脉冲输出能量最高为25.5 mJ,斜率效率为13%。插入声光调Q晶体后获得4.7 mJ的调Q脉冲输出,脉宽为24.8 ns。     

Pump-induced bleaching of the saturable absorber in short-pulse Nd:YAG/Cr/sup 4+/:YAG passively Q-switched microchip lasers

Bleaching of the saturable absorber by pump light increases the length of the pulse generated in a passively Q-switched Nd:YAG/Cr/sup 4+/:YAG microchip laser and decreases the pulse energy. This effect is greatest when transmitted pump light is nearly focused in the Cr/sup 4+/:YAG and when pumping is sufficiently intense to bleach the absorption of the Nd:YAG. Both effects are important in short-pulse microchip lasers. The maximum repetition rate of a passively Q-switched Nd:YAG/Cr/sup 4+/:YAG microchip laser is correlated with the pulsewidth. In general, it decreases as the pulsewidth gets shorter.     

氙灯抽运Nd：GdVO4晶体的脉冲激光性能

利用闪光灯作为抽运源研究了Nd:GdVO4晶体的脉冲激光性能.激光晶体样品尺寸为4 mm×4 mm×6 mm.当输出镜透过率T=15%,抽运能量为 6.32 J时,激光器静态输出能量为 31.7 mJ.对T=7%的输出镜,抽运阈值为 0.13 J.用厚度为 1.5 mm,小信号透过率为 54.7%的Cr4+:YAG晶体片实现了激光器的被动调Q运转,测得动态和静态激光能量输出之比约为1:3.在T=15%的输出镜透过率下,当抽运能量为 3.89 J和 6.32 J时,分别得到了脉冲宽度为 48.0 ns和 39.2 ns的单脉冲输出.     

All-ceramic passively Q-switched Yb:YAG/Cr/sup 4+/:YAG microchip laser

A laser-diode-pumped all-ceramic passively Q-switched Yb:YAG microchip laser with Cr⁴⁺:YAG as a saturable absorber has been demonstrated for the first time. A pulse width of 380 ps and a peak power of over 82 kW at a repetition rate of 12.4 kHz was obtained. A slope efficiency of 37% and an optical-to-optical efficiency of 30% was achieved     

Cr,Tm, Ho:YAG激光器输出的实验研究

为了研究Cr,Tm,Ho:YAG激光器输出脉冲能量和晶体温度的关系,利用有限元的方法计算了不同制冷温度和抽运功率情况下晶体内温度的分布,从而分析温度分布对激光实验输出的影响。控制制冷液温度在15℃、重频5Hz时,获得最大能量为217mJ的脉冲输出,斜效率约为1.4%;而重频10Hz时,最大单脉冲输出仅为56mJ,斜效率约为0.9%。结果表明,制冷温度和频率的增加都将大大增加激光的抽运阈值,同时降低输出效率。     

LD端面抽运Nd:YLF/Nd:YAG多波长脉冲激光器

报道了一台激光二极管(LD)双端面抽运Nd:YLF和Nd:YAG双晶体串接多波长输出脉冲激光器。在抽运能量40.5mJ,电光调Q重复频率500Hz的工作条件下,获得单脉冲能量约为6mJ的1064nm/1053nm双波长激光脉冲输出,光-光转换效率约为14.8%。相同抽运条件下在腔内插入I类相位匹配LBO晶体作为非线性频率转换器,获得了脉冲总能量为3.6mJ的526.5、529.0、532.0nm三波长同时输出,由抽运光到输出绿光脉冲的转换效率约为8.9%,测得光束质量因子分别为M2x=1.61,My2=1.25。     

Dynamics of passively Q-switched microchip lasers

Self-pulsing in passively Q-switched microchip lasers is investigated in detail. The typical range of values of the parameters motivates a new analysis of the laser rate equations. We determine basic properties of the laser intensity oscillations such as threshold conditions, repetition rate, pulsewidth, peak power, and pulse energy. We show that these oscillations appear through a quasi-vertical Hopf bifurcation located slightly above the lasing threshold. Our bifurcation results are verified numerically by modeling a microchip laser experiment with Nd:YAG as the gain medium and YAG:Cr as saturable absorber. Our results agree with the experiment to within 10%     

Internally folded Nd:YAG and Nd:YVO4 lasers pumped bylaser diodes

An efficient, scalable, diode-pumped Nd laser design is reported. The gain element can be longitudinally pumped along five separate axes and is relatively simple to fabricate. Both Nd:YAG and Nd:YVO₄ gain media were evaluated. Using five single-stripe laser diodes to pump the Nd:YAG, 3.94 W of absorbed power produced 2.1 W CW at 1.06 μm. The slope efficiency was 54 percent and the output was TEM₀₀. The threshold power was 40 mW. No evidence of thermal saturation was observed up to the maximum pump power. Repetitively Q-switched operation is also reported. The maximum output power for Nd:YVO₄ obtained with 2.9 W of pump power was 1.3 W. The slope efficiency was 47 percent     

Pulsed optical parametric generation, amplification, and oscillation in monolithic periodically poled lithium niobate crystals

We conducted a series of passively Q-switched Nd:YAG laser pumped optical parametric generation, amplification, and oscillation experiments in monolithic periodically poled lithium niobate (PPLN) crystals. Double-pass optical parametric generation with an effective gain length of 10 cm in a PPLN crystal was performed in comparison with single-pass operation in the same crystal. By seeding a PPLN optical parametric amplifier with a distributed feedback (DFB) diode laser, we produced 200-ps transform-limited laser pulses at 1549.6 nm and observed parametric gain competition at different pump levels. For optical parametric oscillations, we first demonstrated 22% power efficiency from a 2.4-cm intrinsic-cavity PPLN optical parametric oscillator pumped by a 4.2-ns, 10-kW passively Q-switched Nd:YAG laser. Preliminary studies on DFB optical parametric oscillators in PPLN are mentioned. The temporal and spectral properties of these optical parametric generators, amplifiers, and oscillators are characterized and discussed.     

Cr,Tm,Ho:YAG激光器输出的实验研究

对闪光灯泵浦Cr,Tm,Ho:YAG平平腔激光器进行了实验研究。在5Hz室温运行下,获得最大能量为217mJ的脉冲输出,其斜效率约为1.2％。利用有限元方法计算了晶体内温度的分布,分析了晶体内温度对激光阈值和斜效率的影响。模拟了光在腔内的分布,计算热晶体的焦距和晶体内光斑的大小,讨论了晶体热效应对激光输出的影响。