Fano phase resonances in multilayer metal-dielectric compound gratings

Abstract

Phase resonances in multilayer metal-dielectric compound gratings are numerically modeled and described. Additional grating layers allow for more complex types of phase resonances in which light travels in different, circuitous routes through the structure. It is shown that phase resonances produce highly enhanced fields, have a very narrow bandwidth, are Fano resonances with asymmetric line shapes of their reflectance, and produce a complete inversion in the transmittivity/opacity of low loss structures. Several multi-grating structures are numerically modeled that show the addition of more complicated phase resonances as more layers are added to the structure. The dispersion curves of the multiple bands of phase resonances are predicted using an analytical approach and numerical modeling. Applications of the resonance effects are described for optical filters.

Wideband analytical equivalent circuit for one-dimensional periodic stacked arrays

“…In all the above-mentioned models, the structure under analysis involved a single grating surface, leaving aside those situations where coupled gratings are of great interest [7,9,25,[54][55][56][57][58][59]. The latter structures have been proposed for design of artificial materials, filters, and polarizers, and very recently they have been employed to simulate materials with a high permittivity (artificial dielectrics) over a wide terahertz frequency range [60,61].…”

Extraordinary nonlinear transmission modulation in a doubly resonant acousto-optical structure

“…Asymmetry in the unit cell, as compared to the regular symmetric grating, is known to induce a Fano-or phase-resonance [17], the optical signature of which is a narrow dip in the transmission spectrum. According to the value of e, the dip properties can be highly sensitive to local environmental changes imposed by external excitations, such as a mechanical deformation.…”

Controlling Fano resonances in multilayer dielectric gratings towards optical bistable devices

“…Ever since the appearance of the celebrated Fano resonance more than fifty years ago 1 , it has been well-known to be the product of the interference between the discrete state and continuum background in classical or quantum systems. To date, Fano resonance can be achieved not only in classical and quantum systems but also in the photonic structures 2 , such as quantum dots 3 – 5 , two dimensional (2D) planar photonic crystals 6 – 10 , guided-mode resonances in 2D photonic crystals, single- and multi-layer grating structures 11 – 19 , plasmonic nanostructures 20 – 25 , and metamaterials 25 – 29 . One of the major features of the Fano resonance is an asymmetric lineshape in the spectral response which is defined by the quality ( Q ) and asymmetric ( q ) factors.…”

“…These structures have been known as promising designs for many optical applications due to their simple, easy fan-in/out, and their low-cost fabrication processes. Whereas in the multilayer grating structures 12 , 16 – 19 , the phase resonances are added to the structure that produce circulated modes, trapped and stopped waves, and interference between waves reflected back and forth at the guided-mode resonances. Therefore, the corresponding linewidths become significantly reduced, resulting in increased Q -factors.…”