Collective lattice resonances: Plasmonics and beyond

Nanophotonics is an important branch of modern optics dealing with light–matter interaction at the nanoscale. Nanoparticles can exhibit enhanced light absorption under illumination by light, and they become nanoscale sources of heat that can be precisely controlled and manipulated. For metal nanoparticles, such effects have been studied in the framework of thermoplasmonics, which, similar to plasmonics itself, has a number of limitations. Recently emerged all-dielectric resonant nanophotonics is associated with optically induced electric and magnetic Mie resonances, and this field hasdeveloped very rapidly over the past decade. As a result, thermoplasmonics is being complemented by all-dielectric thermonanophotonics with many important applications such as photothermal cancer therapy, drug and gene delivery, nanochemistry, and photothermal imaging. This review paper aims to introduce this new field of non-plasmonic nanophotonics and discuss associated thermally induced processes at the nanoscale.

All-dielectric thermonanophotonics

Resonators of surface plasmons are discussed in this review. Any material supporting the excitation of surface plasmons, either by light, or by electron beams can be used for designing a resonator. Despite the number of materials supporting surface plasmons being restricted to a small number, noble metals, some two-dimensional materials as graphene, transition metal oxides, and several highly doped semiconductors have been used in plasmonic applications. Isolated and coupled metal nanoparticles, arrays of particles on substrates, nanoparticle suspensions, alternated metal and dielectric thin films, dielectric cavities in surfaces of noble metals and sheets and stripes of two-dimensional materials are typical examples of systems used for excitation of plasmonic resonances. These resonances have been used in a fast increasing number of applications: transformation of light beam properties, selective optical induced heating, sensing of chemical or biological compounds, enhancement of non-linear optical excitation in nanomaterials, optical coherence applications in quantum optics. The operating spectral range, variety of sizes, shapes and geometrical configurations that can be tailored and the exceptional optical properties of surface plasmons promote their use in a wide variety of applications at the nanoscale, where other types of resonators cannot be used, or are too inefficient. We review a large variety of plasmonic resonators and their most relevant properties. We first discuss the fundamental properties of the plasmonic resonances, using simple physical models. Then we present a retrospective of applications evidencing the most relevant aspects of interaction of surface plasmons with matter and radiation. Finally we focus the most recent applications covering metamaterials, plasmonic materials with topological properties and resonators supporting plasmon-electron interaction.

https://iopscience.iop.org/article/10.1088/1361-6463/ab96e9/pdf

Plasmonic resonators: fundamental properties and applications

MXenes, an emerging class of two-dimensional materials, exhibit characteristics that promise significant potential for their use in next generation optoelectronic sensors. An interplay between interband transitions and boundary effects offer the potential to tune the plasma frequencies over a large spectral range from the near-infrared to the mid-infrared. This tuneability along with the 'layered' nature of the material not only offer the flexibility to produce plasmon resonances across a wide range of wavelengths, but also add a degree of freedom to the sensing mechanism by allowing the plasma frequency to be modulated. Here we show, numerically, that MXenes can support plasmons in the telecommunications frequency range and that surface plasmon resonances can be excited on a standard MXene coated side polished optical fiber. Thus, presenting the tantalising prospect of highly selective distributed optical fiber sensor networks. 

https://www.nature.com/articles/s41377-022-00710-1.pdf

MXene supported surface plasmons on telecommunications optical fibers

A highly efficient nanocavity formed by optically coupled nanostructures is achieved by optimization of the collective Mie resonances in a one-dimensional array of semiconductor nanoparticles Analysis of quasi-normal multipole modes enables us to reveal the close relation between the collective Mie resonances and Van Hove singularities On the basis of these concepts, we experimentally demonstrate a directional GaAs nanolaser at cryogenic temperatures with well-defined, in-plane emission, which, moreover, can be controlled by selective excitation The lasing threshold is shown to be significantly reduced by optimizing the interparticle gap such that the optimal near-field confinement is achieved at a resonant wavelength corresponding to the highest gain of GaAs We show that the lasing performance of this nanolaser is orders of magnitude better than a nanowire-based laser of the same dimensions The present work provides design guidelines for high performance in-plane emission nanolasers, which may find applications in future photonic integrated circuits

Collective Mie Resonances for Directional On-Chip Nanolasers.

Surface plasmon polaritons (SPPs) are viable candidates for integration into on-chip nano-circuitry that allow access to high data bandwidths and low energy consumption. Metal-insulator-metal tunneling junctions (MIM-TJs) have recently been shown to excite and detect SPPs electrically; however, experimentally measured efficiencies and outcoupling mechanisms are not fully understood. It is shown that the MIM-TJ cavity SPP mode (MIM-SPP) can outcouple via three pathways to i) photons via scattering of MIM-SPP at the MIM-TJ interfaces, ii) SPPs at the metal-dielectric interfaces (bound-SPPs) by mode coupling through the electrodes, and iii) photons and bound-SPP modes by mode coupling at the MIM-TJ edges. It is also shown that, for Al-AlO x -Cr-Au MIM-TJs on glass, the MIM-SPP mode outcouples efficiently to bound-SPPs through either electrode (pathway 2); this outcoupling pathway can be selectively turned on and off by changing the respective electrode thickness. Outcoupling at the MIM-TJ edges (pathway 3) is efficient and sensitive to the edge topography, whereas most light emission originates from roughness-induced scattering of the MIM-SPP mode (pathway 1). Using an arbitrary roughness profile, it is demonstrated that various roughness facets can raise MIM-SPP outcoupling efficiencies to 0.62%. These results pave the way for understanding the topographical parameters needed to develop CMOS-compatible plasmonic circuitry elements.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/advs.201900291

Efficient Surface Plasmon Polariton Excitation and Control over Outcoupling Mechanisms in Metal-Insulator-Metal Tunneling Junctions.

/pdf/directional-launching-of-surface-plasmon-polaritons-by-28ndl0dqhr.pdf

Directional launching of surface plasmon polaritons by electrically driven aperiodic groove array reflectors

To develop methods to generate, manipulate, and detect plasmonic signals by electrical means with complementary metal-oxide-semiconductor (CMOS)-compatible materials is essential to realize on-chip electronic-plasmonic transduction. Here, electrically driven, CMOS-compatible electronic-plasmonic transducers with Al-AlOX -Cu tunnel junctions as the excitation source of surface plasmon polaritons (SPPs) and Si-Cu Schottky diodes as the detector of SPPs, connected via plasmonic strip waveguides of Cu, are demonstrated. Remarkably, the electronic-plasmonic transducers exhibit overall transduction efficiency of 1.85 ± 0.03%, five times higher than previously reported transducers with two tunnel junctions (metal-insulator-metal (MIM)-MIM transducers) where SPPs are detected based on optical rectification. The result establishes a new platform to convert electronic signals to plasmonic signals via electrical means, paving the way toward CMOS-compatible plasmonic components.

CMOS-Compatible Electronic–Plasmonic Transducers Based on Plasmonic Tunnel Junctions and Schottky Diodes

Inelastic quantum mechanical tunneling of electrons across plasmonic tunnel junctions can lead to surface plasmon polariton (SPP) and photon emission. So far, the optical properties of such junctions have been controlled by changing the shape, or the type of the material, of the electrodes, primarily with the aim to improve SPP or photon emission efficiencies. Here we show that by tuning the tunneling barrier itself, the efficiency of the inelastic tunneling rates can be improved by a factor of 3. We exploit the anisotropic nature of hexagonal boron nitride (hBN) as the tunneling barrier material in Au//hBN//graphene tunnel junctions where the Au electrode also serves as a plasmonic strip waveguide. As this junction constitutes an optically transparent hBN–graphene heterostructure on a glass substrate, it forms an open plasmonic system where the SPPs are directly coupled to the dedicated strip waveguide and photons outcouple to the far field. We experimentally and analytically show that the photon emission rate per tunneling electron is significantly improved (~ ×3) in Au//hBN//graphene tunnel junction due to the enhancement in the local density of optical states (LDOS) arising from the hBN anisotropy. With the dedicated strip waveguide, SPP outcoupling efficiency is quantified and is found to be ∼ 80% stronger than the radiative outcoupling in Au//hBN//graphene due to the high LDOS of the SPP decay channel associated with the inelastic tunneling. The new insights elucidated here deepen our understanding of plasmonic tunnel junctions beyond the isotropic models with enhanced LDOS. Enhancement in local density of optical states arising from the optical anisotropy of hexagonal boron nitride significantly improves the emission rates of plasmons and photons in quantum mechanical tunnel junctions.

Thanh Xuan Hoang

Papers

Collective Mie Resonances for Directional On-Chip Nanolasers.

Efficient Surface Plasmon Polariton Excitation and Control over Outcoupling Mechanisms in Metal-Insulator-Metal Tunneling Junctions.

Directional launching of surface plasmon polaritons by electrically driven aperiodic groove array reflectors

CMOS-Compatible Electronic–Plasmonic Transducers Based on Plasmonic Tunnel Junctions and Schottky Diodes

Optical Anisotropy in van der Waals materials: Impact on Direct Excitation of Plasmons and Photons by Quantum Tunneling.