Photonic bands and defect modes in metallo-dielectric photonic crystal slabs

Abstract

Photonic components based on structured metallic elements show great potential for device applications where field enhancement and confinement of the radiation on a subwavelength scale is required. In this paper we report a detailed study of a prototypical metallo-dielectric photonic structure, where features well known in the world of dielectric photonic crystals, like band gaps and defect modes, are exported to the metallic counterpart, with interesting applications to infrared science and technology, as for instance in quantum well infrared photodetectors, narrow-band spectral filters, and tailorable thermal emitters.The idea of reproducing the naturally occurring periodic arrangement of atoms in solid crystals by settling ordered arrays of scattering elements on the light wavelength scale gave origin to the extremely fruitful concept of photonic crystal [1]. Despite the full maturity of this research field, new possibilities keep emerging, regarding the ability of spatially confining otherwise freely propagating photons [2,3]. In original proposals and traditional implementations, photonic crystals relied on dielectric media, mainly owing to the natural interconnection with semiconductor science and technology. However, moving to metallic photonic structures, new physics was developed and technological milestones were set. Starting from the discovery of extraordinary transmission[4], researchers explored the world of periodic arrangements of metallic elements, where the concepts of metamaterials and plasmonics naturally appear.Hybrid metallo-dielectric photonic devices attract attention because the interface between those two classes of materials naturally supports an intense local electric field. This is of clear relevance when the goal is to enhance non-linear effects [5], but also in the realm of linear physics, where the existence of a maximum of the field close to an interface enables the technology for a whole class of photonic devices, like terahertz quantum cascade lasers (QCLs). It is indeed in connection with QCLs and other intersubband devices that certain concepts, like distributed feedback lasers and photonic crystal resonators, have been exported to metallo-dielectric structures [6][7][8].In this paper we theoretically and experimentally analyze a simple one-dimensional metallo-dielectric photonic slab structure, where two key features of photonic crystals -band gap and defect modes -clearly appear. The defect mode is a high Q-factor resonance, whose linewidth and angular acceptance can be tuned at will within wide ranges. The observed phenomenology is general and can be extrapolated to devices working in different wavelength ranges [9,10]; furthermore, small modifications to the studied prototypical passive component could directly lead to operating devices for the infrared * simone.zanotto@sns.it spectral range. Thanks to the anticipated resonance tunability, metallo-dielectric photonic crystal defects can be very useful for the development of guided-mode resonance filters (GMRF) [11,12] and ...

Striking properties of light transmitted by a double period nanoslit structure under evanescent incidence

“…, having converted the variable λ d into θ −1 via equation (24). The maxima corresponding to FP resonances are clearly appreciated, together with the phase resonance minima.…”

“…Not only numerical and experimental results have proved the existence of such anomalies, but also a variety of simplified models have been successfully proposed to provide physical insight into the underlying physics involved [19][20][21][22][23]. The potential applications of double-period metallic structures include linear and nonlinear quantum well infrared photodetectors, guided mode resonance filters and tailorable thermal emitters [24]. Also, dielectric double-groove gratings have been proposed as input/output couplers for dielectric substrates [25,26], and multilayer metal-dielectric compound gratings promise applications such as tunable antennas, multiwavelength filters and highly sensitive chemical and biological sensors [27].…”

Saturation and bistability of defect-mode intersubband polaritons

“…As reported in Ref. 17, the resonance quality factor is governed by the parameters d and N Bragg ; on the three samples we realized, we kept fixed d = 0.4 and employed N Bragg = 2, 4, and 6. As it can be noticed in the figure inset, the resonant field distribution is mainly overlapped with the semiconductor membrane, which is nanostructured implementing a multi-quantum well (MQW, consisting of 65 repetitions of 6.8/15 nm GaAs/Al 0.33 Ga 0.67 As well/barrier pairs).…”

“…Less attention has instead been devoted to study how the cavity quality factor influences intersubband polariton devices; perhaps, this is due to the lack of direct mechanisms for tuning the Q-factor of LC resonators and of patch cavities. However, we recently reported about two mechanisms for easily tuning the radiative Q-factor of photonic crystal-based resonators, both in the direction of smaller and of larger Q's 16,17 . It is widely recognized that the quality factor plays a significant role in cavity quantum electrodynamics and in photonics, hence, it is expected to strongly influence intersubband polariton devices.…”

“…In this article we will instead explore the effect of the damping rate mismatch, relying on the tunability of defect-mode photonic crystal resonators 17 . In a lowintensity transmission experiment, defect-mode intersubband polaritons appear as usual as a doublet of spectral features, whose contrast is governed by the damping rate mismatch.…”