Technical Papers and Presentations

Recently, the researchers usually use the hydrodynamic Drude model (HDM) to investigate the nonlocal optical response of metallic nanostructure. The advantage of the HDM is easy to implement numerical calculation for larger and more complex-shaped nanoplasmonic structures. For the HDM, it is predicted that the nonlocal response blueshifts the resonance peak, modifies the electric field enhancement, gives a series of subsidiary peaks above plasma frequency, and influence the nonlinear optical phenomena of the metallic nanostructure and so on. However, the HDM only considers the convective current due to the quantum pressure, losing sight of any currents due to the classical diffusion effect. In fact, the quantum and classical effects on the optical properties of metallic nanostructure are always coexistence and interaction with each other, and have profound implications for our understanding of light-matter interplay. Thus, it’s meaningful and indispensable to study the diffusion under the nonlocal optical response. In this work, we use COMSOL Multiphysics® software to investigate the effect of induced electron diffusion on the optical properties of metallic nanostructure based on the generalized nonlocal optical response(GNOR) model which takes into account both quantum pressure convection and induced electron diffusion. We compare the numerical results between the GNOR and the HDM, of isolate nanowires, and of nanowires on a semi-infinite dielectric substrate .The results show that the electron diffusion which is usually disregarded can lead to significant effect on the optical properties of metallic nanostructure.