VSRR for isotropic absorption and nanophotonic sensor

Abstract

Metamaterials have been realized for exotic optical phenomena which can not be found in nature, such as negative refractive index and cloaking. Nowadays, people intend to be more precisely from fundamental physical response to specific functionalities in metamaterials on demand for the development on practical applications, such as optical switches, phase gradient surfaces[1,2], optical modulators, polarizer and wave plate. One of the potential applications is the metamaterial based perfect absorber (MPA)[3]. Due to the strong electromagnetic field confinement arising from surface plasmon resonance, MPA provides a benefitting way for enhancing the efficiency in solar energy capture, nanoplasmonic sensor and bolometer. The commonly utilized structural configuration for MPAs is incorporating a metamaterial array with a perfect reflective mirror separated by a dielectric spacer. Because of the near-field interaction between metamaterials and its mirror images, a strong plasmon field confinement is involved and therefore dramatically enhances the absorption intensity. However, both the electric and magnetic responses play an important role to those of electromagnetic media, especially for the nonlinearity responses. Vertical split-ring resonator (VSRR) attracts a wide interest because it found out that the magnetic reciprocal coupling of incident light [4,5].