Surface Plasmon Polariton Assisted Optical Switching in Noble Metal Nanoparticle Systems: A Sub-Band Gap Approach

Abstract

Understanding the light-matter interaction at nanometre scale is a fundamental issue in optoelectronics and nanophotonics which are prerequisites for advanced sensor applications of optical switching. The electrical transport process in noble metal-insulator nanocomposite or dispersed noble metal nanocluster in dielectric matrix is discussed. Banking on high value of third-order nonlinear susceptibility, optical switching was reported in the percolation threshold of noble metals in dielectric matrices. The optical switching originating from the excitation of the surface plasmon was recorded for metal-oxide-metal tunnelling junctions. The surface plasma polariton (SPP) in the form of drifting hot electrons across the oxide barrier and tunnelling to the counter electrode in the evanescent field of surface plasmon resonance (SPR) was made responsible for electrical transport mechanism. These models, for the first time, are discussed in ambit of having a sub-band gap feature in the SPP assisted photoresponse where transport of electrical carriers may manifest either at the percolation threshold with enhanced electro-magnetic field, and in the form of tunnelling current through the potential barrier at the Fermi level or in the propagation of plasmon coupled electrons at SPR for metal-dielectric composites.