Interplay between evanescence and disorder in deep subwavelength photonic structures

Sheinfux, Hanan Herzig; Kaminer, Ido; Genack, Azriel Z.; Segev, Mordechai

doi:10.1038/ncomms12927

Cited by 35 publications

(34 citation statements)

References 46 publications

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“…Moreover, in connection with our assumption of TE polarization, once again to facilitate direct comparison with the results from previous related studies [20,24,26,27], we note that enhanced nonlocality generally occurs for the transverse-magnetic polarization as well [20], although its visibility may be less pronounced [21].…”

Section: Some Remarkssupporting

confidence: 79%

“…Our outcomes constitute a first step toward extending the previous studies on periodic [20][21][22][23][24][25][26] and randomly disordered [27,28] geometries to the intermediate realm of "orderly disorder" and, albeit focused on a specific geometry, provide some generally applicable tools.…”

Section: Discussionmentioning

confidence: 93%

“…First, one may argue that the material parameters considered in the multilayers (especially ε a = 1) are not realistic for an experimental validation. As previously mentioned, the main motivation behind this parameter choice was to facilitate direct comparison with the results in previous studies on periodic and random scenarios [20,24,26,27]. As also demonstrated by the experimental studies in Refs.…”

Section: Some Remarksmentioning

confidence: 97%

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Aperiodic order induced enhancement of weak nonlocality in multilayered dielectric metamaterials

2018

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Recent studies on fully dielectric multilayered metamaterials have shown that the negligibly small nonlocal effects (spatial dispersion) typically observed in the limit of deeply subwavelength layers may be significantly enhanced by peculiar boundary effects occurring in certain critical parameter regimes. These phenomena, observed so far in periodic and randomly disordered geometries, are manifested as strong differences between the exact optical response of finite-size metamaterial samples and the prediction from conventional effective-theory-medium models based on mixing formulae. Here, with specific focus on the Thue-Morse geometry, we make a first step toward extending the studies above to the middle-ground of aperiodically ordered multilayers, lying in between perfect periodicity and disorder. We show that, also for these geometries, there exist critical parameter ranges that favor the buildup of boundary effects leading to strong enhancement of the (otherwise negligibly weak) nonlocality. However, the underlying mechanisms are fundamentally different from those observed in the periodic case, and exhibit typical footprints (e.g., fractal gaps, quasi-localized states) that are distinctive of aperiodic order. The outcomes of our study indicate that aperiodic order plays a key role in the buildup of the aforementioned boundary effects, and may also find potential applications to optical sensors, absorbers and lasers. * vgaldi@unisannio.it 1 arXiv:1811.01258v1 [physics.optics]

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Section: Some Remarkssupporting

confidence: 79%

Section: Discussionmentioning

confidence: 93%

Section: Some Remarksmentioning

confidence: 97%

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Aperiodic order induced enhancement of weak nonlocality in multilayered dielectric metamaterials

2018

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“…Overall, the assumed parameter regime is rather unusual, as the phase-accumulation mechanism is essentially dominated by the discrete jumps (Fresnel-type reflection/transmission) at the layer interfaces rather than the delay acquired via propagation through the (deeply subwavelength) layers. In previous studies on periodic and aperiodic structures [8,14,16,17,20], it was shown that such mechanism can lead to the buildup of boundary effects that can substantially enhance the (otherwise negligible) nonlocal effects, thereby yielding strong departures of the optical response from the EMT predictions. These effects tend to be particularly enhanced nearby the critical angle defining the total-internal-reflection condition for the effective medium, θ c = arcsin ε /ε e = 60 o .…”

Section: Generalitiesmentioning

confidence: 99%

“…Interestingly, these phenomena are not limited to periodic arrangements. In particular, anomalous Anderson localization was observed theoretically [16] and experimentally [17] in randomly disordered dielectric multilayers, once again in a deeply subwavelength regime where conventional EMT predicts instead a moderately transmissive response. More recently, inspired by the permeating concept of "quasicrystals" [18,19], we have started exploring aperiodically ordered multilayer geometries, lying in between perfect periodicity and random disorder.…”

Section: Introductionmentioning

confidence: 99%

Effects of deterministic disorder at deeply subwavelength scales in multilayered dielectric metamaterials

2020

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It is common understanding that multilayered dielectric metamaterials, in the regime of deeply subwavelength layers, are accurately described by simple effective-medium models based on mixing formulas that do not depend on the spatial arrangement. In the wake of recent studies that have shown counterintuitive examples of periodic and aperiodic (orderly or random) scenarios in which this premise breaks down, we study here the effects of deterministic disorder. With specific reference to a model based on Golay-Rudin-Shapiro sequences, we illustrate certain peculiar boundary effects that can occur in finite-size dielectric multilayers, leading to anomalous light-transport properties that are in stark contrast with the predictions from conventional effective-medium theory. Via parametric and comparative studies, we elucidate the underlying physical mechanisms, also highlighting similarities and differences with respect to previously studied geometries. Our outcomes may inspire potential applications to optical sensing, switching and lasing.

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Emerging Long‐Range Order from a Freeform Disordered Metasurface

et al. 2022

Advanced Materials

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existence of defect or disorder will inevitably result in the destruction of intrinsic photonic bandgaps, thus impairing the practical performance of desired design for wave propagation. [2] By contrary, recent developments in micro-and nanophotonics have demonstrated that disorder structure with spatially inhomogeneous material, including random or chaotic structures, could be well utilized as an another degree of freedom to yield various new optical phenomena. [3][4][5] Particularly, a variety of nonconventional optical functionalities have been proposed in diverse areas of optical applications, ranging from optical Anderson localization in deep subwavelength photonic structures, [6] broadband momentum transformation and spatiotemporal instability suppression in a chaotic optical microcavity, [7,8] and optical transition in the disordered plasmonic system [9,10] to perfect focusing in disordered media. [11,12] Consisting of arrays of artificial nanostructures (or meta-atoms), metasurface can arbitrarily manipulate the amplitude, phase, and polarization of the incident light field at subwavelength scale [13][14][15] and therefore has been widely applied to planar imaging, [16][17][18][19] meta-holograms, [20][21][22] quantum optics, [23][24][25][26] and complex beam generators. [27][28][29][30][31] Most recently, disorder engineering has been introduced into metasurface by randomly manipulating the spatially inhomogeneous phase retardation of meta-atoms, Recently, disordered metasurfaces have attracted considerable interest due to their potential applications in imaging, holography, and wavefront shaping. However, how to emerge long-range ordered phase distribution in disordered metasurfaces remains an outstanding problem. Here, a general framework is proposed to generate a spatially homogeneous in-plane phase distribution from a disordered metasurface, by engineering disorder parameters together with topology optimization. As a proof-of-concept demonstration, an all-dielectric disordered supercell metasurface with relatively homogeneous in-plane phase fluctuation is designed by disorder parameter engineering, manifesting as polarization conversion-dependent random scattering or unidirectional transmission. Then, a topology optimization approach is utilized to overcome the lattice coupling effect and to further improve the homogeneity of complex electric field fluctuation. In comparison with the initial supercell metasurface, both the phase fluctuation range and the relative efficiency of the topologyoptimized freeform metasurface are significantly improved, leading to a long-range ordered electric field distribution. Moreover, three experimental realizations are performed, all of which agree well with the theoretical results. This methodology may inspire more exotic optical phenomena and find more promising applications in disordered metasurfaces and disordered optics.

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Interplay between evanescence and disorder in deep subwavelength photonic structures

Cited by 35 publications

References 46 publications

Aperiodic order induced enhancement of weak nonlocality in multilayered dielectric metamaterials

Aperiodic order induced enhancement of weak nonlocality in multilayered dielectric metamaterials

Effects of deterministic disorder at deeply subwavelength scales in multilayered dielectric metamaterials

Emerging Long‐Range Order from a Freeform Disordered Metasurface

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