Harmonically pump a femtosecond optical parametric oscillator to 1.13 GHz by a femtosecond 515 nm laser

We demonstrate a harmonically pumped femtosecond optical parametric oscillator(OPO)laser using a frequency-doubled mode-locked Yb:KGW laser at a repetition rate of 75.5 MHz as the pump laser.Based on a bismuth borate nonlinear crystal,repetition rates up to 1.13 GHz are realized,which is 15 times that of the pump laser.The signal wavelength is tunable from 700 nm to 887 nm.The maximum power of the signal is 207 m W at the central wavelength of 750 nm and the shortest pulse duration is 117 fs at 780 nm.The beam quality(M^2 factor)in the horizontal and vertical directions of the output beam are 1.077 and 1.141,respectively.     

A 515-nm laser-pumped idler-resonant femtosecond BiB3O6 optical parametric oscillator

We report on an idler-resonant femtosecond optical parametrical oscillator(OPO)based on BiB₃O₆(BiBO)crystal,synchronously pumped by a frequency-doubled,mode-locked Yb:KGW laser at 515 nm.The idler wavelengths of OPO can be tuned from 1100 nm to 1540 nm.At a repetition rate of 75.5 MHz,the OPO generates as much as 400 mW of idler power with 3.1 W of pump power,the corresponding pulse duration is 80 fs,which is 1.04 times of Fourier transform-limited(FTL)pulse duration at 1305 nm.In addition,the OPO exhibits excellent beam quality with M²<1.8 at 1150 nm.To the best of our knowledge,this is the first idler-resonant femtosecond OPO pumped by 515 nm.     

皮秒激光泵浦的亚10fs钛宝石激光器

研制了高稳定Nd∶YVO_4皮秒激光振荡器,并在15 W、808nm激光泵浦下得到6 W的连续锁模皮秒激光输出,光-光效率为40%.对该皮秒激光进行单通放大后得到14 W的基频光输出,倍频后可以得到7 W的532nm皮秒激光,用作钛宝石振荡器的泵浦源.在4.5 W的皮秒532nm激光泵浦下,结合腔外压缩,得到了脉宽为9.4fs、平均功率为150mW的脉冲序列输出.调节钛宝石振荡器的腔长使其与皮秒振荡器的腔长一致时,可实现自触发克尔透镜锁模.实验结果表明皮秒激光泵浦可以有效地触发钛宝石激光器的自动锁模,输出飞秒脉冲序列.     

超强激光在均匀等离子体中的背向拉曼散射放大机制

使用等离子体背向受激拉曼散射对激光进行放大时,等离子体的密度、温度和长度都会对激光的放大效果产生影响.为了探究等离子体密度对结果的影响,本文使用一维粒子模拟程序模拟了波长为800 nm的泵浦激光入射到均匀等离子体中,等离子体密度和泵浦光光强对散射光光谱的影响.模拟结果表明,等离子体密度降低会导致散射光的波长变短,而泵浦光的光强在一定范围内降低会增加散射光中背向散射光的比例.通过分析散射光的光强和等离子体的密度,发现前向拉曼散射是等离子体密度变化的原因.模拟结果对等离子体背向受激拉曼散射放大的实验研究具有重要的指导意义.