半透明介质内激光脉冲链传输过程的叠加机理

Superposition Mechanism of Pulse Train's Transmission in Semitransparent Medium

根据光波在介质内的散射、折射特点,分析了脉冲链在参与性介质内经界面反射和介质散射后的叠加机理。导出了脉冲链入射非散射性半透明平板时透射比和反射率的解析解。利用间断有限元法和时间平移叠加法计算了脉冲链在一维散射性介质平板内传输的透射比和反射率。结果表明由于介质内部入射光与介质的相互影响,脉冲链受界面的反射和内部介质的散射,分裂成一系列时滞不同的子光波。经过不同的光学行程后,子光波叠加成离开平板的反射光波和透射光波。叠加效果随介质散射系数、脉冲宽度和脉冲时间间距发生变化。通过调节脉冲链的脉冲宽度和脉冲时间间距可得到不同波形的反射波和透射波。

Based on the scattering and refraction characteristics of optical waves in medium, the superposition mechanism of pulse trains after interface reflection and medium scattering is researched. Analytical solutions of the transmittance and reflectance of pulse trains in non-scattering semitransparent slab are deduced. The discontinuous finite element method and time shift and superposition method are used to calculate the transmittance and reflectance in one-dimensional scattering slab medium. The results show that the pulse train, reflected by interface and scattered by medium is split into a series of sub-lightwaves with different time delays due to the interaction of incident light and medium. After passing different optical path, the sub-lightwaves are superposed as the reflected and transmitted light waves leaving the slab. The superposition effects vary with the variation of scattering coefficient, pulse width and time interval. Regulating pulse width and time interval of pulse trains will produce the reflected and transmitted light waves with different wave shapes.