Multiresonant plasmonics with spatial mode overlap: overview and outlook

Abstract

Plasmonic nanostructures can concentrate light and enhance light-matter interactions in the subwavelength domain, which is useful for photodetection, light emission, optical biosensing, and spectroscopy. However, conventional plasmonic devices and systems are typically optimized for the operation in a single wavelength band and thus are not suitable for multiband nanophotonics applications that either prefer nanoplasmonic enhancement of multiphoton processes in a quantum system at multiple resonant wavelengths or require wavelength-multiplexed operations at nanoscale. To overcome the limitations of “single-resonant plasmonics,” we need to develop the strategies to achieve “multiresonant plasmonics” for nanoplasmonic enhancement of light-matter interactions at the same locations in multiple wavelength bands. In this review, we summarize the recent advances in the study of the multiresonant plasmonic systems with spatial mode overlap. In particular, we explain and emphasize the method of “plasmonic mode hybridization” as a general strategy to design and build multiresonant plasmonic systems with spatial mode overlap. By closely assembling multiple plasmonic building blocks into a composite plasmonic system, multiple nonorthogonal elementary plasmonic modes with spectral and spatial mode overlap can strongly couple with each other to form multiple spatially overlapping new hybridized modes at different resonant energies. Multiresonant plasmonic systems can be generally categorized into three types according to the localization characteristics of elementary modes before mode hybridization, and can be based on the optical coupling between: (1) two or more localized modes, (2) localized and delocalized modes, and (3) two or more delocalized modes. Finally, this review provides a discussion about how multiresonant plasmonics with spatial mode overlap can play a unique and significant role in some current and potential applications, such as (1) multiphoton nonlinear optical and upconversion luminescence nanodevices by enabling a simultaneous enhancement of optical excitation and radiation processes at multiple different wavelengths and (2) multiband multimodal optical nanodevices by achieving wavelength multiplexed optical multimodalities at a nanoscale footprint.

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“…The figures briefly describe the coupling mechanism between a graphene plasmonic mode and a molecular vibrational mode. According to the mode-coupling theory [ 35 ], the infrared absorption spectroscopy of sub-nanometric volumes protein molecules can be effectively enhanced by the strong coupling between the graphene plasmonic mode and the molecular vibrational mode due to the strong plasmonic field confinement squeezed inside the bilayer graphene plasmon cavity.…”

Investigation of the Plasmonic Interaction of Gold Nanoparticles Toward Plasmonic Photothermal Therapeutics

“…During the plasmonic interaction, several types of plasmonic modes are generated, such as localized surface plasmon (LSP), surface plasmon polariton (SPP), and delocalized Bloch plasmonic modes, etc. [5]. This interaction between nanoparticles can be defined by using bonding and antibonding modes of homodimer and heterodimers respectively [6][7][8].…”

Multiresonant plasmonic nanostructure for ultrasensitive fluorescence biosensing

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