Low‐Loss Hybrid High‐Index Dielectric Particles on a Mirror for Extreme Light Confinement

Abstract

The quest for enhancing light–matter interactions at the nanoscale has led scientists to nanophotonic systems that support the smallest possible modes, which are currently realized via particle‐on‐mirror (PoM) geometries using plasmonic particles. The drawback of metallic PoM systems is the large absorption/scattering ratio due to the significant Ohmic losses inherent to plasmonics. Here, an alternative dielectric PoM composed of a high‐index dielectric nanodisk on top of a metallic mirror is realized. Custom‐shaped high‐quality dielectric colloidal nanoparticles are fabricated and dispersed on a mirror to fully unlock the potential of PoM systems. This hybrid device combines the large field enhancement and extreme localization of plasmonic systems with the low absorption of dielectric nanoresonators. By means of far‐field scattering and near‐field cathodoluminescence spectroscopy, the nature of the modes supported by the hybrid PoM are revealed. Utilizing enhanced spectroscopies, such as Raman and fluorescence, these hybrid‐PoM systems are used in proof‐of‐principle applications. A comparison with Au antennas indicates that the hybrid PoM system presents efficiencies and optical characteristics comparable or superior to those of more conventional purely plasmonic systems, opening new avenues for low‐loss light control at the deep nanoscale level.

Optical Rotation and Thermometry of Laser Tweezed Silicon Nanorods

“…The particles were modeled as cylinders with variable diameter D and height h and with incident polarization either along or perpendicular to the rotational symmetry axis. The experimentally measured dielectric function of poly-Si 46 was used in the simulations.…”

Colloidal Mie Resonators for All‐Dielectric Metaoptics

“…In contrast, a nanodisk has a surface contact with a metal film and the hot spot is much larger. Maimaiti et al [ 60 ] produced a colloidal solution of Si nanodisks by the method shown in Figure 3b and deposited it on metal surface to produce a nanodisk on a mirror structure (Figure 6d). In this configuration, the resonator can couple more efficiently to normal incident light (Figure 6e).…”

“…To simultaneously achieve a strong field confinement and a small nonradiative loss, a hybrid system composed of a dielectric nanoparticle placed on a metal mirror (NPoM) was proposed. [ 60,82,83 ] Yang [ 81 ] performed detailed comparison of the Q‐factor, the mode volume, and the radiative Purcell factor between dielectric, dielectric–metal, and all‐metal systems and demonstrated that a larger Purcell factor and a higher quantum efficiency can be simultaneously achieved in a dielectric NPoM. The large Purcell factor of a dielectric NPoM was experimentally verified by Maimaiti et al [ 60 ] by means of cathodoluminescence mapping.…”

“…[ 60,82,83 ] Yang [ 81 ] performed detailed comparison of the Q‐factor, the mode volume, and the radiative Purcell factor between dielectric, dielectric–metal, and all‐metal systems and demonstrated that a larger Purcell factor and a higher quantum efficiency can be simultaneously achieved in a dielectric NPoM. The large Purcell factor of a dielectric NPoM was experimentally verified by Maimaiti et al [ 60 ] by means of cathodoluminescence mapping. The quantum efficiency enhancement is also experimentally demonstrated in a Si NPoM system formed by a solution‐based process (Figure 9c).…”

Nanoantenna‐Enhanced Light‐Emitting Diodes: Fundamental and Recent Progress

“…[ 83,84 ] Meanwhile, dielectric nanoantenna could also generate resonance modes upon incident light illumination, producing local electric field enhancement at the vicinity of nanoantenna. [ 85,86 ] On top of that, dielectric nanoantenna could generate both electric and magnetic types of resonance mode depending on the displacement current distribution inside the nanoantenna ( Figure a), whereas the metallic nanoantenna is, in general, dominated by the electric type of the resonance.…”