Coupled plasmon-waveguide resonance (CPWR) biosensor uses the evanescent wave at the waveguide boundary to excite surface plasmon wave (SPW), which couples the energy of the optical field in the waveguide to surface plasmon wave to produce surface plasmon resonance (SPR). In this paper, BK7 prism was combined with Ag/SiO2 structure, Ag nanoparticles were embedded on the surface of SiO2 waveguide layer to form a new CPWR biosensor. Ag nanoparticles can produced light-induced located surface plasmon resonance(LSPR). Resonance coupling between LSPR and CPWR can enhanced the penetration depth and figure of merit (FOM) of traditional biosensors. The finite-difference timedomain (FDTD) method was used to simulate the enhancement behavior of Ag nanoparticles, and to explore the influence of Ag nanoparticles density on the sensor performance. It was found that the penetration depth of the Ag nanoparticle enhanced CPWR biosensor was 1.75 times of that of the traditional CPWR biosensor, and the highest figure of merit was 1.8 times of that of the latter.
The Switching mechanism of a-Si memristor is based on the electrochemical metallization (ECM) effect. After application of a constant bias, the metal ions oxidized on the surface of the electrode migrates to the amorphous silicon layer, which not only lead to the resistive switching behavior, but also the change of optical parameters of switching material. Here, a novel film memristor with optical readout functionality has been set up by combining a silicon prism with Ag/a-Si/Al structure. The attenuation of the reflected light from the device dependence on surface plasmon resonance (SPR) effect on interface of silver layer which is sensitive to the refractive index of the a-Si layer. The change of the reflectance spectrum of the memristor under different bias voltages was simulate by means of finite-difference time-domain (FDTD) method, and the influence of the thickness of the amorphous silicon film and the silver film on the intensity of the reflected light was analyzed.