抽运能量对受激布里渊散射光限幅特性的影响

采用布里渊噪声起源模型,数值模拟了受激布里渊散射介质CCl4对波长1064nm的Nd：YAG纳秒激光脉冲的传输特性及光限幅特性。入射抽运脉冲能量较低时,非线性介质对纳秒激光脉冲呈光学透明。入射抽运脉冲能量高于受激布里渊散射产生阈值后,透射脉冲峰值受限,脉宽压缩,能量趋于饱和,说明该光学系统同时具有光功率限幅和能量限幅的光限幅特性。利用理论模型模拟了如下光限幅参量：透射脉冲峰值功率、透射能量、能量透射率、脉宽压缩率依赖抽运光能量的变化关系。相应的理论模拟计算结果由实验进行验证,实验结果与理论模拟相符合。     

Chaos in Fiber-Optic Stimulated Brillouin Scattering without External Feedback in Large Nonlinear Refractive Index Regime

Stokes dynamics in stimulated Brillouin scattering generated in optical fibers is analyzed over a wide range of nonlinear refractive indices under a no feedback condition. The Stokes fluctuation becomes complicated as the nonlinear refractive index increases. Chaotic behavior appears without external feedback at a large nonlinear refractive index of 1×10^-19 m²/V² with pump power larger than 0.3 W.     

强激光放大系统中C_3H_6O的高效SBS效应研究

在强激光放大系统中,使用C_3H_6O作为非线性介质,获得了高效的SBS效应,Stokes波一次反射率～60％,末级激光放大器对Stokes波的能量放大率达到3,Stokes波脉宽压缩率为4,功率放大系数达到12,经SBS后,激光近场强度分布得到明显改善,在强泵浦下,Stokes波了现高频调制。对实验结果及其应用前景进行了讨论。     

Chaos in Fiber-Optic Stimulated Brillouin Scattering Dependent on Pump Power, Nonlinear Refractive Index, Feedback Power, and Fiber Length

Dependence of Stokes dynamics in stimulated Brillouin scattering generated in optical fibers on the pump power, the nonlinear refractive index, the fiber length, and the feedback powers of the pump and the Stokes is numerically analyzed. The Stokes power fluctuation becomes complicated and chaotic as the nonlinear refractive index and the input pump power increase in a fiber of sufficient length. The Stokes dynamics is less complicated and the chaotic region decreases in a pump power-reflectivity domain in a short fiber. The chaotic behavior appears without regular tendency in relation to the feedback power. Taking into account the pump feedback, the chaotic region expands and some Stokes behaviors are different in the P_P-R domain graph, compared with the case with the Stokes feedback alone, although this feedback does play an essential role in Stokes dynamics.     

三倍频Nd:YAG激光抽运氧气中的受激拉曼和布里渊散射

报道了三倍频脉冲Nd：YAG激光（355nm）在两种不同带宽模式下抽运氧气中受激拉曼散射（SRS）和受激布里渊散射（SBS）的实验研究。在宽带（约1cm^-1）抽运模式下,只测到了前向受激拉曼散射,而没有观察到后向散射,其一级和二级斯托克斯最大能量转换效率可达22％和8％。在窄带（约0．003cm^-1）模式下,前向、后向受激拉曼散射和受激布里渊散射都测量到了,但大部分抽运能量都转换到受激布里渊散射,其转换效率可达67％。测量了两种带宽模式下各散射组分在它们最佳转换时的波形;窄带情况下后向受激拉曼散射和受激布里渊散射的脉宽分别可压窄至1．5ns和2．3ns,不到抽运脉宽的三分之一,使得受激布里渊散射峰值功率可大大高于抽运功率。对氧气中前向、后向受激拉曼散射和受激布里渊散射之间的竞争进行了讨论。     

三倍频Nd∶YAG激光抽运氧气中的受激拉曼和布里渊散射

报道了三倍频脉冲Nd∶YAG激光(355 nm)在两种不同带宽模式下抽运氧气中受激拉曼散射(SRS)和受激布里渊散射(SBS)的实验研究。在宽带(约1 cm-1)抽运模式下,只测到了前向受激拉曼散射,而没有观察到后向散射,其一级和二级斯托克斯最大能量转换效率可达22%和8%。在窄带(约0.003 cm-1)模式下,前向、后向受激拉曼散射和受激布里渊散射都测量到了,但大部分抽运能量都转换到受激布里渊散射,其转换效率可达67%。测量了两种带宽模式下各散射组分在它们最佳转换时的波形;窄带情况下后向受激拉曼散射和受激布里渊散射的脉宽分别可压窄至1.5 ns和2.3 ns,不到抽运脉宽的三分之一,使得受激布里渊散射峰值功率可大大高于抽运功率。对氧气中前向、后向受激拉曼散射和受激布里渊散射之间的竞争进行了讨论。