SBS新介质C_4Cl_6参数确定及性能研究

Study on parameters and performances of SBS medium C_4Cl_6

从介质对光的吸收机理出发,研究了吸收系数较小的受激布里渊散射(SBS)新介质六氯-1,3-丁二烯(C4Cl6)。通过基本的物理参数,确定了入射光波长为1 064 nm时C4Cl6的SBS参数,其吸收系数约为0.003 cm-1,声子寿命约为0.25 ns,增益系数约为4.9 cm.GW-1。分析了入射光波长与介质SBS参数的关系,布里渊频移与入射光波长成反比,声子寿命与入射光波长的平方成正比,增益系数一般与入射光波长无关。在单池SBS系统中,利用Nd:YAG调Q激光器研究了C4Cl6的SBS性能。实验结果表明:由于其吸收系数小,与具有相同增益系数的H2O比较,C4Cl6具有较高的能量反射率(饱和能量反射率大于55%)和较宽的SBS脉宽;由于其声子寿命短,与具有相同吸收系数的CS2比较,C4Cl6的SBS波形上升时间较短。吸收系数小和声子寿命短的特点,使C4Cl6适合作为放大池介质,这对优化SBS介质选取,提高SBS系统性能具有一定意义。

The stimulated Brillouin scattering （SBS） medium hexachlorobuta-1,3-diene （C4Cl6） with little absorption coefficient is studied in terms of the absorption theory of medium to the light. Through basic physical parameters, the SBS parameters of C4Cl6 with the incident beam wavelength of 1 064 nm are determined. The absorption coefficient is 0. 003 cm^-1 , the phonon lifetime is 0.25 ns and the gain coefficient is 4.9 cm · GW^-1. Whereas the Brillouin frequency is inversely proportional to the incident beam wavelength and the phonon is proportional to its square, the gain coefficient is wavelength-independent. In the singlecell SBS system pumped by Nd： YAG Q-switched laser, the SBS performances of C4 Cl6 are studied. The results show that the saturation energy reflectivity of C4 Cl6 is above 55%, well exceeding that of H2O. As to the SBS pulse, the width is broader than that of H2O and the rise time is shorter than that of CS2. The characteristics of small absorption coefficient and short phonon lifetime, making C4 Cl6 suitable for the amplifier medium, will be of importance in optimizing the choice of SBS medium and improving the SBS system performance.