利用激光反射法探测微小振动

利用激光反射法改进了激光监听器在音质等方面的监听效果。采用硅光电池探测激光器反射的光斑，使用遥控微调电机调节光斑对准，由声卡采集探测信号，电路采用巴特沃斯带通滤波器，还利用Matlab中的audio weighting filter进行信号处理和滤波。实验结果表明监听信号准确、清晰。     

Active modulation of plasmonic signal with a subwavelength metal/nonlinear dielectric material/metal structure

<正>Light propagation through a metal/nonlinear dielectric material/metal(M-NL-M) structure is numerically studied.The design parameters of the M-NL-M structure are found with the waveguide theory so that the structure only supports the symmetric surface plasmon polaritons(SPP(0)) mode and the antisymmetric surface plasmon polaritons(SPP(1)) mode.The coupling between the two modes within the M-NL-M structure is exploited.Through controlling the propagation constants of the two modes with the intensity-dependent dielectric constant of the nonlinear Kerr material,an effective all-optical control of plasmonic signal modulator can be realized with this M-NL-M structure.