Experimental demonstration of high sensitivity refractive index sensing based on magnetic plasmons in a simple metallic deep nanogroove array

Abstract

A high-performance wide-angle refractive index sensor based on a simple onedimensional (1D) metallic deep nanogroove array with a high aspect ratio is experimentally fabricated and demonstrated. The 1D deep groove array is featured by the excitation of magnetic plasmon (MP), referring to an effective coupling of incident electromagnetic waves with a strong magnetic response induced inside the deep grooves. Utilizing MP resonances that are extremely sensitive to the surrounding dielectric medium, we successfully achieve a refractive index sensitivity (RIS) up to ∼1300 nm/RIU, which is higher than that of most experimentally designed plasmonic sensors in the infrared region. Importantly, benefiting from angle-independent MP resonances with strong confinement of the magnetic field inside the deep grooves and strong electric field localization at the groove openings, we demonstrate wide-angle sensing capability valid in a broadband infrared region with an excellent linear dependence on the change of the refractive index. Such a MP-based sensor, together with its simple 1D flat nature and ease of fabrication, has great potential for the practical design of high sensitive, cost-effective and compact sensing devices.

Bandwidth tunability of graphene absorption enhancement by hybridization of delocalized surface plasmon polaritons and localized magnetic plasmons

“…As indicated by the arrows, the light is normally incident on the studied structure, with its electric and magnetic fields perpendicular and parallel to the slit, respectively. Under such an incident condition, localized MPs can be excited within the slit [48,49], and delocalized SPPs can be excited on the surface of the silver substrate. We perform relevant numerical simulations by using the commercial software (https:// www.…”

Perfect Absorption and Refractive-Index Sensing by Metasurfaces Composed of Cross-Shaped Hole Arrays in Metal Substrate

“…Obviously, the currents near the cross-shaped hole are relatively stronger, and create a loop on the xz plane, as indicated by the red arrows in Figure 2b. The current loop will produce a substantial magnetic moment, which is able to response to the magnetic field of incident light, and thus form a magnetic resonance [77]. The magnetic resonance is the physical origin of the absorption peak centered at the wavelength of λ 1 .…”

Light–Matter Interactions between Germanium Nanocavities and Quantum Dots at Visible Wavelengths

“…Exploring light–matter interactions has become a long-term research subject for a deeper understanding of quantum physics and nanophotonics, and it is the need of developing future optical devices with remarkable performance and advanced functions. − Generally speaking, resonances are the cornerstone in the field of photonics, and light–matter interactions could be considered as resonance mode hybridization between a resonant cavity and a quantum emitter. ,− When a quantum emitter is moved from infinity to the vicinity of a resonant cavity, the optical properties of the former will be strongly modified by the enhanced electromagnetic field from the latter. − A platform is needed that can concentrate the light within a few nanometers and exchange energy with the excitons of these two-level systems. ,,, Extremely small features from noble metallic nanostructures are preferred to provide a localized electromagnetic enhancement leading to a small mode volume, such as the gap in the groove, particle dimer, or particle-on-mirror. ,− In particular, grooves with nanometer dimensions are simple to fabricate and provide electromagnetic “hotspots”, which have great potential applications in optical nonlinearity enhancement, index sensing, and ohmic absorption. − But how to deal with the heat issues arising from the collective behavior of electrons in a resonant cavity at visible wavelengths is always a disturbing problem . A possible solution to this problem could be to utilize all-dielectric components with a high refractive index instead of a noble metal. − All-dielectric nanogrooves have been used to improve the light management in solar cells and boost the second-order harmonic generation of two-dimensional transition-metal dichalcogenides. − A tunable scattering dark state has been achieved by integrating a Mie resonator within an all-dielectric nanogroove .…”