Localized defect modes in dual-periodical multilayer structures based on porous silicon

Abstract

We present an experimental study of the resonance modes in dual-periodical multilayer structures based on porous silicon. These multilayered structures are composed by stacking N times two substructures A, and B, i.e., A n B m N . The A n and B m are in turn composed of two different period units, a and b, respectively, where subscripts n and m are the period number in the a and b substructures. Both substructures a and b consist of a pair of alternating layers with high and low refractive indices n 1 and n 2 , respectively. The thickness parameters of the dielectric layers in a and b are all different. We observe several resonance transmission peaks due to the periodical repetition of the A n B m structure. The number of resonance peaks, their full width at half-maximum (FWHM), etc., can be controlled by selecting the structural parameters of the system. The experimental data are in good agreement with those calculated using the transfer matrix method. These optical superlattices are very promising, since they can be designed so that the reflectance response presents a determined number of resonance modes in the most important window for optical communications, making them good candidates for direct applications.

Demonstration of photon Bloch oscillations and Wannier-Stark ladders in dual-periodical multilayer structures based on porous silicon

“…The decreasing or the increasing number of layers of the substructure, acting as a defect in the system (substructure B for the samples considered here), results in the widening or narrowing of the peaks and consequently, the value of FWHM [ 34 ].…”

“…Recently, Pérez et al [34] reported DP structures from PSi multilayers. Dual-periodic structure (Figure 1) is composed of two substructures, A and B , repeating alternatively in the sequence $A_n{B}_m{A}_n{B}_m\mathrm{...}{A}_n{B}_m={\left(A_n{B}_m\right)}^N$.…”

“…The optical properties of dual-periodical (DP) structures have been theoretically and experimentally reported by several groups [ 32 , 33 ]. Recently, Pérez et al [ 34 ] reported DP structures from PSi multilayers. Dual-periodic structure (Figure 1 ) is composed of two substructures, A and B , repeating alternatively in the sequence .…”

“…When identical A n B m structures are coupled, a degenerate mode repulsion arises. Each degenerate optical resonance splits up and a miniphotonic band forms [ 32 - 34 ]. Due to the periodicity of the structure, the miniphotonic bands are separated by photonic band gaps in which propagation is prohibited.…”

“…By adjusting the structural parameters, it is possible to tune the number, frequency, and full width at half-maximum (FWHM) of the resonance modes, opening the possibility to fabricate optical filters based on porous silicon multilayers. Such DP photonic structures are very promising in the field of optoelectronics, optical communications, and optical biosensors [ 34 ].…”