Exciton-Polaritons with Magnetic and Electric Character in All-Dielectric Metasurfaces

Abstract

Exciton−polaritons are hybrids of light and matter formed at the strong coupling regime that exhibit interesting phenomena such as enhanced transport, long-range energy transfer, and nonlinear response. These properties make exciton−polaritons very promising quasiparticles for the development of novel optoelectronic applications in the so-called polaritonic devices. However, strong coupling is significantly damped by the absorption losses of the system, which lead to short-lived exciton−polaritons. Here, we demonstrate strong coupling between excitons in organic molecules and all-dielectric metasurfaces formed by arrays of polycrystalline silicon nanoparticles supporting Mie surface lattice resonances (MSLRs). Compared to Mie resonances in individual nanoparticles, MSLRs have extended mode volumes and much larger quality factors, which enables to achieve collective strong coupling with very large coupling strengths and Rabi energies. Moreover, the presence of electric and magnetic Mie resonances in high refractive index dielectric nanoparticles introduces a new degree of freedom in light−matter interaction. We show the hybridization of excitons with electric and magnetic MSLRs, to form exciton−polaritons with an electric or magnetic character. Our results demonstrate the potential of all-dielectric metasurfaces as novel platform to investigate and manipulate exciton−polaritons in low-loss polaritonic devices.

Bound States in the Continuum in the Visible Emerging from out-of-Plane Magnetic Dipoles

“…Because dielectric meta-atoms, such as nanoparticles, can support both electric dipole (ED) and magnetic dipole (MD) resonances, elaborated design of meta-atoms to tune the interference between dipoles results in exotic optical effects. Examples of these effects are the Kerker effect or zero-backscattering, [1][2][3][4][5][6][7][8][9][10][11][12] surface lattice resonances, [13][14][15] and non-radiating anapole modes. 16 Of particular interest is the emergence of optical bound states in the continuum (BICs), which are dark modes non-excitable from outside.…”

Low‐Threshold Bound State in the Continuum Lasers in Hybrid Lattice Resonance Metasurfaces

“…The applications of BICs in many fields, especially topological photonics, have been widely discussed. [ 12,17,18 ] By using a topological design to create BICs, different types of metasurfaces or photonic crystals can be used in various applications, such as photonic integrated circuits, [ 19–22 ] sensors, [ 23–25 ] nonlinear effect enhancement, [ 26–30 ] low‐threshold lasers, [ 31,32 ] and vortex lasers. [ 33–36 ] Optical BICs have attracted attention not only as resonators for lasing but also as sources of thermal emission.…”

Disentangling cathodoluminescence spectra in nanophotonics: particle eigenmodes vs transition radiation

“…39,40 All-dielectric nanodevices are thus proposed as promising alternatives to plasmonics, with possible applications in biosensing, 41,42 nanoantennas, 43,44 slow light, 45 thermo-optic tuning, 46 ultraviolet interband plasmonics, 47 fluorescence control, [48][49][50] and Mie-exciton strong-coupling phenomena. [51][52][53][54] CL measurements are performed with the set-up shown schematically in the left-hand sketch of Figure 1a (see Methods for details). Si nanospheres of radius R (prepared in an agglomeration-free colloidal solution; 55 typical SEM image is shown in the middle panel of the figure), placed on a thin Si 3 N 4 membrane, are exposed to swift electrons travelling at velocity v (with a corresponding relativistic factor β = v/c, where c is the speed of light in vacuum), for different impact parameters b (see righthand schematic of Figure 1a), corresponding to either non-penetrating or penetrating electron beams.…”