Transparent Metal Slabs Based on Light-tunneling Mechanism in Metamaterials

Abstract

[evdate 2012-10-03] Croucher Advanced Study Institute on New Materials and New Concepts for Controlling Light and Waves. Talk no.9Host: HKUST Institute for Advanced Study.

Sponsor: The Croucher Foundation.

Abstract: Metals have much larger third-order nonlinear susceptibility than those of typical dielectrics. However, when the thickness is much larger than the skin depth, the metal is nearly opaque due to high reflectance and such nonlinear effect is inaccessible. In this talk, we will discuss our recent studies on zero-reflection or transparent phenomenon in an optical thick metal (M) slab based light-tunneling mechanism in a pairing structure made of a permittivity (ε)-negative (ENG) and a permeability (μ)-negative (MNG) metamaterial, as proposed first by Alu and Engheta. We show theoretically and experimentally, that a one-dimensional dielectric photonic crystal (PC) (CD)n may mimic a lossless optical ENG or MNG metamaterial in the band-gap region. Then a visible-light tunneling mode can be realized by pairing a MNG-like PC with a metal slab behaving as an optical ENG metamaterial, leading to the transparent phenomenon in an optical thick metal. Moreover, transmittance as high as T = 33% and T =38% are observed at visible light λ = 589 nm for M=Ag, with thickness d = 60.2 nm in a heterostructure M(CD)n and d = 83.1 nm in a sandwich structure (CD)nM(DC)n, respectively. The transmittance is more than 200 times larger than that of same thickness of Ag without tunneling in the late case. Possible applications based on transparent metal or magnetic metal slabs, e.g., enhancing optical properties such as absorption, nonlinearity and Faraday effects; realizing all-optical diode action and nonlinear excitation of surface plasmon polaritons are also discussed.

Duration: 28 min.