Resonant optical transmission through hole‐arrays in metal films: physics and applications

Abstract

Extraordinary optical transmission through an array of holes in a metal film was reported by Ebbesen and coworkers in 1998. Since that work there has been abundant research activity aimed at understanding the physics and at the development of the many applications associated with this phenomenon, hence the topic of this review. The study of hole-arrays in a metal is not new -theoretical contributions on a small-hole array date back to Lord Rayleigh's description of Wood's anomaly in 1907 and there has been considerable research on metal meshes and holearrays since 1962. Bethe's theory, adapted to treat hole-arrays, is the simplest theoretical description of the transmission resonance. Following a description of this basic theory, we present the research on the additional effects from variations in real metal properties at different wavelengths, film thickness, holeshape and lattice configuration. The many promising applications being developed using hole-arrays are examined, including polarization control, filtering, switching, nonlinear optics, surface plasmon resonance sensing, surface-enhanced fluorescence, surface-enhanced Raman scattering, absorption spectroscopy, and quantum interactions. Finally, the various approaches, developments in hole-array fabrication, and integration of hole-arrays into devices are described. (top left) Schematic of resonant transmission through nanohole array using scanning electron microscope image of as-fabricated sample. (top right) Microfluidic chip incorporating nanohole arrays. (bottom) Composite image of array of nanohole arrays used as sensors in a immunoassay-like microfluidic device, showing (left to right) schematic of microfluidic layout, microscope image of arrays in microfluidic channels, and laser transmission modified by adsorbed molecules.

Optimization of Optoelectronic Plasmonic Structures

“…Such a plasmonic structure not only supports nearfield plasmonic modes but also facilitates far-field light coupling through Bragg scattering [5]. In a carefully designed hole-array structure, standing surface waves can be formed on the metal surface due to the cavity-like effect, generating an enhanced transverse plasmonic mode.…”

Seeing protein monolayers with naked eye through plasmonic Fano resonances

“…By exploiting these Fano resonances and the associated high contrast ratios of the on-resonance to the off-resonance transmissions (Wood's anomaly), we demonstrate direct detection of a single monolayer of antibodies with naked eye. Such sharp resonances could open door to a new generation of ultraportable and ultrasensitive plasmonic biosensors for detection of biologically important molecules and pathogens (27,28). A crucial prerequisite for the record high sensitivities is the suppression of the scattering losses caused by surface roughness and in-homogeneities.…”

Stacked dielectric gratings for sub-wavelength surface field synthesis

“…It is one thing to generate very narrow spots-there are several known ways to do this, such as using tiny holes in thin metal sheet [25], which is a very energy inefficient process. The advantage of the grating approach is that the spots are generated not through some masking process but via spectral synthesis, in an efficient way.…”