Graphene Q-switched 0.9-μm Nd:La_(0.11)Y_(0.89)VO_4 laser

Graphene saturable absorber(SA) is used as the passive Q-switcher of a 0.9-μm solid-state laser.When the laser medium is a Nd:La0.11Y0.89VO4 crystal,the initial transmittance of the graphene SA is 78%;at an absorbed pump power of 7.62 W,the maximum average output power,largest pulse energy,and minimum pulse width are 0.62 W,2.58μJ,and 84 ns,respectively.This study shows that graphene is a promising and cost-saving SA for 0.9-μm pulse generation.     

Steady-state Raman gain in visible and near-infrared waveband of Sr WO_4 and Ba WO_4 crystals

The steady-state stimulated Raman scattering （SRS） gain with different excitation wavelengths ranging from 400 to 1100 nm of tungstate crystals, SrWO4 and BaWO4, is systematically researched. As excitation frequency is close to electronic transition frequency, molecular polarizability is not a constant, which has to be taken into account in our work. The experiment and theory agree well with each other and show that SRS gain is not only proportional to Stokes light frequency, but is also inversely proportional to biquadratic excitation frequency.     

新型钨青铜型晶体Ca0.28Ba0.72Nb2O6的生长研究

研究了Ca0.28Ba0.72Nb2O6 (CBN-28)多晶料的制备和单晶的生长,用提拉法成功生长出CBN-28单晶.从X射线粉末衍射数据计算了CBN-28晶体的晶胞参数,并对其粉末衍射图各衍射峰进行了指标化.CBN晶体属四方晶系4mm点群.晶胞参数为a=1.2432(±2)nm,c=0.3957(±1)nm.采用浮力法测得其平均密度为5.372g/cm3,测得其莫式硬度为7,并通过测量CBN-28的介电性质,确定其居里点为260℃.