Nonradiating photonics with resonant dielectric nanostructures

Abstract

Nonradiating sources of energy have traditionally been studied in quantum mechanics and astrophysics, while receiving a very little attention in the photonics community. This situation has changed recently due to a number of pioneering theoretical studies and remarkable experimental demonstrations of the exotic states of light in dielectric resonant photonic structures and metasurfaces, with the possibility to localize efficiently the electromagnetic fields of high intensities within small volumes of matter. These recent advances underpin novel concepts in nanophotonics, and provide a promising pathway to overcome the problem of losses usually associated with metals and plasmonic materials for the efficient control of the light-matter interaction at the nanoscale. This review paper provides the general background and several snapshots of the recent results in this young yet prominent research field, focusing on two types of nonradiating states of light that both have been recently at the center of many studies in all-dielectric resonant meta-optics and metasurfaces: optical anapoles and photonic bound states in the continuum. We discuss a brief history of these states in optics, their underlying physics and manifestations, and also emphasize their differences and similarities. We also review some applications of such novel photonic states in both linear and nonlinear optics for the nanoscale field enhancement, a design of novel dielectric structures with high-resonances, nonlinear wave mixing and enhanced harmonic generation, as well as advanced concepts for lasing and optical neural networks. arXiv:1903.04756v1 [physics.optics]

Transverse Scattering and Generalized Kerker Effects in All-Dielectric Mie-Resonant Metaoptics

“…Moreover, we design nearly invisible metasurfaces with zero reflection and near 100% transmission governed by the simul-taneous cancellation of both forward and backward scattering in each meta-atom. The transverse scattering is accompanied by a strong near-field localization inside the particles, and it is conceptually similar to the optical anapoles [24,25]. Such interference-driven effects are of a high demand for various applications including four-wave mixing [26] and enhanced second-harmonic generation [27].…”

Can a Nonradiating Mode Be Externally Excited? Nonscattering States versus Embedded Eigenstates

“…Introduction -The ability to tailor optical scattering in anomalous and extreme ways, beyond what is achievable with conventional optical materials and structures, has been for several years one of the fundamental goals of optical metamaterials and nanophotonic systems [1]. Rapid progress in these fields has enabled the realization of a plethora of anomalous scattering effects, including invisibility [2][3][4][5][6], ultra-sharp Fano scattering resonances [7,8], non-scattering anapole scatterers [9][10][11][12][13][14][15][16], and bound states in the continuum or embedded eigenstates [17][18][19][20][21][22]. Scattering engineering plays a fundamental role in modern photonics research, for applications spanning from wavefront manipulation [23] and optical signal processing [24,25], to energy harvesting [26] and sensing [27], to mention just a few.…”

“…This growing area of research holds the potential to enable important advances in nanophotonics and quantum optics, for extreme light confinement in small open structures. Intriguingly, recent works (e.g., [9][10][11][12][13][14][15][16]) have discussed the possibility to observe and excite radiationless anapole modes supported by engineered scatterers.…”

Photosensitive chalcogenide metasurfaces supporting bound states in the continuum

“…The tight confinement of the local electromagnetic fields and multiple interferences available in resonant dielectric nanostructures and metasurfaces can boost many optical effects and offer novel opportunities for the subwavelength control of lightmatter interactions. In particular, recently emerged concept of bound states in the continuum (BICs) in nanophotonics enables a simple approach to achieve high-Q resonances (or quasi-BICs) for various platforms ranging from individual dielectric nanoparticles [7] to periodic arrangements of subwavelength resonators such as metasurfaces or chains of particles [8][9][10][11][12]. Moreover, very recently it was revealed [13] that metasurfaces created by seemingly different lattices of dielectric meta-atoms with broken in-plane inversion symmetry can support sharp high-Q resonances arising from a distortion of symmetry-protected BICs.…”