Light-field enhancement on thin and ultra-thin high-index dielectric slabs with rectangular nano-pits

Abstract

We closely study the local amplifications of visible light on a thin dielectric slab presenting a sub-wavelength array of small, rectangular, bottom-closed holes. The high-quality Fabry-Perot resonances of eigen modes which vertically oscillate, and their corresponding near-field maps, especially inside the voids, are numerically quantified with RCWA and analytically interpreted through a quasi-exact modal expansion. This last method gives explicit opto-geometrical rules allowing to finely understand the general trends in 1D and 2D. In more advanced examples, we show that multi-cavity and/or slightly thicker two-dimensional gratings may generate anomalously frequencysusceptible surfaces over a broad spectral range. Also, dielectric membranes a few nanometers thick only, can catch light, with tremendous enhancements of the electric field intensity (> 10 6 ) that largely extends in the surrounding space.

Resonant amplified seismic response within a hill or mountain

“…It so happens that similar problems are of great interest in other fields of physics such as electrodynamics (e.g, optics and microwaves) [37,211,240,210,220,77,223,365,108,316,295,6,366,367,203,345,294,112,134,204,76,81,198,199,238,114,180,276,59,90,230,250,253,261,262,272,280,294,324,338,346,347,348,349,355], acoustics [338,331,236,337,121,…”

“…In recent years, research in these fields has largely switched to the near-field, stimulated by the discovery of such spectacular effects as SERS (Surface-Enhanced Raman Scattering) [211,240,315,345,365], enhanced frequency-selective (total) absorption (as applied notably to energy harvesting [172,198] or noise reduction [121,122,357,198]), and negative refraction [180,207] in media (recently dubbed metamaterials [368,381]) bounded by, or including, periodic structures [90,211,210,220,77,222,365,108,316,295,6,366,367,203,345,294,112,134,204,76,81,198,199,54,80,97,134,207,261].…”

“…The core of the present contribution is the notion of 'resonance' and its connection with wavefield amplification [274,116,339,155,351,352,353,133,213,222,221,223,102,331,332,246,51,385,188,369,31,89,142,201,208,209,210,211,236,337,354,366,367,391,80,81,91,120,124,125,126,158,159,171,177,182,185,187,198,199,…”