Extraordinary optical absorption through subwavelength slits

Abstract

We report on the ability of resonant plasmonic slits to efficiently concentrate electromagnetic energy into a nanoscale volume of absorbing material placed inside or directly behind the slit. This gives rise to extraordinary optical absorption characterized by an absorption enhancement factor that well exceeds the enhancements seen for extraordinary optical transmission through slits. A semianalytic Fabry-Perot model for the resonant absorption is developed and shown to quantitatively agree with full-field simulations. We show that absorption enhancements of nearly 1000% can be realized at 633 nm for slits in aluminum films filled with silicon. This effect can be utilized in a wide range of applications, including high-speed photodetectors, optical lithography and recording, and biosensors.

Broadband polarization-independent resonant light absorption using ultrathin plasmonic super absorbers

“…By structuring noble metal surfaces on the subwavelength scale, localized and delocalized surface plasmon resonances can be designed to produce high absorption on otherwise refl ective surfaces. Resonant light absorption in metallic structures has been widely studied both theoretically and experimentally in arrays of metallic gratings 1 -5 , nanoparticles 6,7 and subwavelength slits 8,9 . Metamaterials are also promising candidates to enhance electromagnetic wave absorption, and have been shown to yield perfect absorption at microwave 10 , terahertz 11 and infrared 12 -14 frequencies.…”

Proposal for verifying dipole properties of light-harvesting antennas

“…We hence consider only figure 2 (a). The notch is essential not only for concentrating but also to take out the energy received by the LH1 − RC complex [28]. The molecule of 1PYH shown in Figure 1 also has a notch.…”

Nanoplasmonics and its Applied Devices

“…He-Ne laser with a power of 2mW at a wavelength of λ = 633nm is transmitted through a polarizer, Polarizer polarizes to transverse magnetic (TM) mode and is passed to a high refractive index (n p = 1.845) prism at [90] 0 and through a sensor chip. The sensor chip consists of a glass slide and with a PNIPAAm hydrogel film and glass is coated with a gold layer of thickness between 37 and 45 nm.…”

“…White J.S and et al explored a deep subwavelength volume nanoplasmonic structure: a single isolated slit in a metallic film on an absorbing substrate [90]. They carried out their analysis based on finite-difference frequency-domain (FDFD) simulations [91] of slits generated in an Al film on a Si substrate.…”

“…White JS et al [90] investigate scattering coefficients of the metal-dielectric-metal system (MDM) [ Figure 17 (b)] for Fabry-Perot model. Plane wave electric field polarized normal to x direction strikes the top surface with permittivity constant ε 1 .…”