高密度平面靶等离子体中激光驱动冲击波加速离子的能谱展宽

本文对超短超强激光脉冲辐照高密度等离子体产生的静电冲击波加速离子的能谱展宽机理进行了数值研究.着重讨论了三种冲击波加速离子的能谱展宽机理:能量沉积到离子中使得冲击波前沿不断减速,被加速离子与背景粒子的碰撞,以及高能离子到达靶背面时受到鞘层场进一步加速.还研究了驱动激光脉冲宽度对冲击波加速离子能谱宽度的影响. 关键词： 激光等离子体 冲击波加速 能谱展宽     

High Power Continuous-Wave Actively Mode-Locked Diode-Pumped Nd:YAG Laser

We demonstrate a diode-pumped cw mode-locked Nd：YAG by an acousto-optic mode locker. A mode-locked pulse with duration of 345 ps and output power of 12 W is obtained. The resonator design shows three advantages： a larger mode volume, high stability against thermal lens fluctuations, and excellent beam quality with TE00 mode. Different from previous active mode locking designs, we employ a frequency stabilizer and a phase-lock loop circuit to ensure the mode locking stable operation.     

基于双壁碳纳米管低阈值1895nm锁模激光器

结合特殊设计的低阈值五镜折叠腔,利用垂直生长法自制的双壁碳纳米管,并将其作为可饱和吸收体在Tm,Ho…LLF激光器中实现了连续锁模运转。在连续激光运转下,吸收抽运阈值低至59 mW,光-光转化效率为30.09%。在腔内插入饱和吸收体后,吸收抽运阈值提高至107mW。当吸收抽运功率大于1562mW时,激光运转进入稳定的连续锁模状态,对应锁模脉冲的重复频率为100 MHz,脉冲宽度约为515ps;当吸收抽运功率达到2 W时,最高输出功率为234mW,中心波长为1895nm,对应最大单脉冲能量为2.34nJ。     

Kerr-lens mode-locked polycrystalline Cr:ZnS femtosecond laser pumped by a monolithic Er:YAG laser

We demonstrated a Kerr-lens mode-locked polycrystalline Cr:ZnS laser pumped by a narrow-linewidth linearpolarised monolithic Er:YAG nonplanar ring oscillator operated at 1645 nm. With a 5-mm-thick sapphire plate for intracavity dispersion compensation, a compact and stable Kerr-lens mode-locking operation was realised. The oscillator delivered 125-fs pulses at 2347 nm with an average power of 80 m W. Owing to the special polycrystalline structure of the Cr:ZnS crystal, the second to fourth harmonic generation was observed by random quasi-phase-matching.     

基于单壁碳纳米管调Q锁模低阈值Tm,Ho:LiLuF_4激光器

采用垂直生长法制作的单壁碳纳米管作为可饱和吸收体,结合特殊的低阈值谐振腔设计,首次在Tm,Ho:LiLuF_4全固态激光器中实现了低阈值自启动被动调Q锁模运转.以波长可调的掺钛蓝宝石固体激光器作为抽运源,选用1.5%,3%和5%的输出耦合镜,获得了出光阈值低至52,59和62mW的连续光输出.采用3%输出耦合镜,获得了阈值低至250mW的稳定调Q锁模脉冲输出,调Q包络的脉宽为2μs,调Q包络下锁模脉冲重复频率178.6MHz,最大输出功率154mW,最大的单脉冲能量为0.86nJ,调制深度接近100%.     

2089 nm调Q锁模Tm,Ho∶CaYAlO4激光器

首次采用氧化石墨烯可饱和吸收体作为锁模启动元件在Tm,Ho∶CaYAlO4激光器中实现了稳定的被动调Q锁模运转。在3%输出耦合镜下,Tm,Ho∶CaYAlO4固体激光器获得了最低为293 mW的连续光出光阈值。在腔内引入氧化石墨烯可饱和吸收体后,当吸收抽运功率增大到1859 mW时,Tm,Ho∶CaYAlO4激光器进入稳定的调Q锁模运转状态。当抽运功率达到3 W时,获得中心波长为2089 nm、斜效率为10.1%、对应最大输出功率为213 mW的被动调Q锁模脉冲,重复频率为100 MHz,调Q包络中锁模脉冲的调制深度接近100%。