This paper investigates analytically the electric field distribution of graded spherical core-shell metamaterials, whose permittivity is given by the graded Drude model. Under the illumination of a uniform incident op...This paper investigates analytically the electric field distribution of graded spherical core-shell metamaterials, whose permittivity is given by the graded Drude model. Under the illumination of a uniform incident optical field, the obtained results show that the electrical field distribution in the shell region is controllable and the electric field peak＇s position inside the spherical shell can be confined in a desired position by varying the frequency of the optical field as well as the parameters of the graded dielectric profiles. It has also offered an intuitive explanation for controlling the local electric field by graded metamaterials.展开更多
For breaking through the sensitivity limitation of conventional surface plasmon resonance （SPR） biosensors, novel highly sensitive SPR biosensors with Au nanopartieles and nanogratings enhancement have been proposed...For breaking through the sensitivity limitation of conventional surface plasmon resonance （SPR） biosensors, novel highly sensitive SPR biosensors with Au nanopartieles and nanogratings enhancement have been proposed recently. But in practice, these structures have obvious disadvantages. In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parame- ters on the performance is investigated by using rigorous coupled wave analysis （RCWA）. Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters. The results indicate that significant sensitivity increase is associated with localized surface plasmons （LSPs） excitation mediated by nanoholes. Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves＇ width are obtained simultaneously under optimized structural parameters.展开更多
基金Project supported by the National 863 Project of China (Grant Nos. 2009AA09Z102 and 2008AA09A403)the RGC General Research Fund of the Hong Kong SAR Government
文摘This paper investigates analytically the electric field distribution of graded spherical core-shell metamaterials, whose permittivity is given by the graded Drude model. Under the illumination of a uniform incident optical field, the obtained results show that the electrical field distribution in the shell region is controllable and the electric field peak＇s position inside the spherical shell can be confined in a desired position by varying the frequency of the optical field as well as the parameters of the graded dielectric profiles. It has also offered an intuitive explanation for controlling the local electric field by graded metamaterials.
基金the Nanotechnology Pro-grams of Science and Technology Commission of Shang-hai Municipality under Grant No.0652nm004.
文摘For breaking through the sensitivity limitation of conventional surface plasmon resonance （SPR） biosensors, novel highly sensitive SPR biosensors with Au nanopartieles and nanogratings enhancement have been proposed recently. But in practice, these structures have obvious disadvantages. In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parame- ters on the performance is investigated by using rigorous coupled wave analysis （RCWA）. Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters. The results indicate that significant sensitivity increase is associated with localized surface plasmons （LSPs） excitation mediated by nanoholes. Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves＇ width are obtained simultaneously under optimized structural parameters.
