Plasmonic Surface Lattice Resonances Research Articles

Correction: Plasmonic surface lattice resonances in nanoparticle arrays

Correction: Plasmonic surface lattice resonances in nanoparticle arrays

Plasmonic surface lattice resonances in nanoparticle arrays

Plasmonic surface lattice resonances in nanoparticle arrays

High Q-Factor Plasmonic Surface Lattice Resonances in Colloidal Nanoparticle Arrays.

Surface lattice resonances (SLRs) sustained by ordered metal arrays are characterized by their narrow spectral features, remarkable quality factors, and the ability to tune their spectral properties based on the periodicity of the array. However, the majority of these structures are fabricated using classical lithographic processes or require postannealing steps at high temperatures to enhance the quality of the metal. These limitations hinder the widespread utilization of these periodic metal arrays in various applications. In this work, we use the scalable technique of template-assisted assembly of metal colloids to produce plasmonic supercrystals over centimeter areas capable of sustaining SLRs with high Q factors reaching up to 270. Our approach obviates the need for any postprocessing, offering a streamlined and efficient fabrication route. Furthermore, our method enables extensive tunability across the entire visible and near-infrared spectral ranges, empowering the design of tailored plasmonic resonant structures for a wide range of applications.

Multi-mode detection of iodine based on Au@Ag nanoparticle array with highly sensibility and stability using plasmonic surface lattice resonances

Designing a sensor to rapidly and simply detect iodine (I2) in liquid and gaseous phase with excellent sensitivity, high stability, and low cost at room temperature is highly desirable. Herein, a two-dimensional Au@Ag nanoparticle ordered array was prepared by template method combined with chemical reduction for detecting I2 at room temperature. Due to the ordered structure, a plasmonic surface lattice resonances (PSLR) peak appeared in extinction spectrum of the Au@Ag nanoparticle ordered array. When the ordered array exposed to I2, the Ag shell would react with I2 to form AgI, thus leading to a change in the dielectric medium surrounding the Au nanoparticles. This change would cause a variation of color and a shift of PSLR peak, realizing multi-mode detection of liquid and gaseous I2 at room temperature without any sophisticated instrument. With the increase of I2 concentration, the color of the Au@Ag nanoparticle array changed from red to yellow-green. Meantime, the PSLR peak displayed highly sensitive redshift with a larger offset (about 156 nm) and intense signal strength. Moreover, due to the ordered array structure, the PSLR peak possessed good uniformity and stability. Therefore, the PSLR peak was more suitable for detecting I2 in a large concentration region. Furthermore, the practical application of the present prepared Au@Ag nanoparticle array was explored by detecting gaseous I2 at room temperature. It was found that the Au@Ag nanoparticle array possessed high sensitivity to gaseous I2 with a detection limit reaching to trace level (1 ppb), suggesting tremendous potential for real-world application.

Optical Characterisation of Plasmonic Indium Lattices Fabricated Via Electrochemical Deposition

Indium is an emerging plasmonic material that offers to extend the plasmonic applications given by gold and silver from the visible to the ultraviolet spectral range, with applications in imaging, sensing, and lasing. However, due to the high-vapor pressure/low melting temperature of indium, nanofabrication of pre-defined metallic indium nanostructures is non-trivial.In this work, we show the potential of selective area electrochemical deposition for the manufacturing of large-area arrays of indium pillars, which can be used for plasmonic applications. We combine electrochemical deposition with substrate-conformal imprint lithography to realize these large-scale indium nanoparticle arrays, having well-defined dimensions. This template growth results into well-defined hexagonal array of pillars with a mean height of 235 nm having a standard deviation of 60 nm.To highlight the potential of this electrochemical-based technique for plasmonic applications, we have performed angle-dependent extinction measurements using s-polarized light and using a RI matching oil. We found that these indium nanopillar arrays exhibit a strong plasmonic response due to the coupling to the plasmonic surface lattice resonances (SLRs). Furthermore, we have simulated the optical response of this indium nanopillar array using finite difference time domain (FDTD) simulations. In these simulations, we included the morphology obtained from SEM and the electrical permittivity of elemental indium. We found that the simulated extinction spectra agree well with the experimentally obtained spectra at 0˚ and 8˚ incidence, despite the polydispersity of the indium pillar height and defects in the hexagonal array.Our results therefore demonstrate the possibility of realizing large-area fabrication of indium plasmonic nanoparticles, which can be used for plasmonic applications. Given the low-cost and scalable nature of this technique, this work opens new possibilities in the design and fabrication of large-area plasmonic metasurfaces that operate in the UV spectral range. Future extensions of this work may leverage the indium mask-constrained growth to tailor even further the shape of the nanoparticle and hence give a powerful tuning knob to tailor plasmonic resonances.

Optical Binding of Metal Nanoparticles Self‐Reinforced by Plasmonic Surface Lattice Resonances

AbstractOptical binding of metal nanoparticles (NPs) provides a promising way to create tunable photonic materials and devices, where the ultrastrong interparticle interaction is generally attributed to the localized surface plasmon resonances of NPs. Here, it is revealed that the optical binding of metal NPs can be self‐reinforced by the plasmonic surface lattice resonances (PSLRs) associated with the discrete NP arrays. Through simulations and experiments, it is demonstrated that PSLRs can spontaneously arise in optically bound gold NP chains with just a few NPs when they are relatively large, e.g., 150 nm in diameter. Additionally, the PSLRs are enhanced by increasing the chain length, leading to stronger optical binding stiffness. These results reveal a previously unidentified factor that contributes to the ultrastrong optical binding of metal NPs. More importantly, this study presents a prospect for building freestanding and reconfigurable NP arrays that naturally support PLSRs for sensing and other applications.

Morphology Engineering for High-Q Plasmonic Surface Lattice Resonances with Large Field Enhancement

Plasmonic surface lattice resonances (SLRs) have endowed plasmonic systems with unprecedently high quality (Q) factors, giving rise to great advantages for light–matter interactions and boosting the developments of nanolaser, photodetector, biosensor and so on. However, it still lacks exploration to develop a strategy for achieving large electric field enhancements (FEs) while maintaining high Q factors of SLRs. Here, we investigate and verify such a strategy by engineering morphologies of plasmonic lattice, in which the influences of geometrical shapes, cross-section areas and structural compositions of particles are investigated. Firstly, we found that the Q factor of a plasmonic SLR is inversely proportional to the square of the cross-section area of the cell particles in the studied cases. Secondly, larger FEs of SLRs appear when the separated cell particles support stronger FEs. By combining these effects of particle morphology, we achieve a plasmonic SLR with Q factor and FE up to 2100 and 592 times, respectively. Additionally, supported by the derived connections between the Q factors and FEs of SLRs and the properties of cell particles, the property optimizations of SLRs can be done by optimizing the separated particles, which are distinctly time-saving in simulations. These results provide a guideline for the design of high-performance optical nanocavities, and can benefit a variety of fields including biosensing, nonlinear optics and quantum information processing.

Hybridization of surface lattice modes: towards plasmonic metasurfaces with high flexible tunability

Abstract When assembled in periodic arrangements, metallic nanostructures (NSs) support plasmonic surface lattice (SL) resonances resulting from long-range interactions these surface lattice resonances differ radically from localized surface plasmon (LSP). Similarly to the hybridization of LSP resonances, observed in short-range interactions, we demonstrate the possibility to generate a hybridization of surface lattice (SL) plasmon resonances, by the excitation of grazing order diffraction within the metasurface. This hybridization leads to the emergence of bonding and anti-bonding modes. If hybridization of LSP modes has been widely described in recent literature, there is still no experimental proof-of-concept reporting such hybridization with SL plasmon resonances. We fill this gap in the present paper by considering surfaces made of binary arrays with unit cells made of two gold disks of distinct diameters. We demonstrate the possibility to maximize or cancel the interaction between the hybridized SL resonances by simply controlling the distance between particles. All our experimental results are supported by FDTD calculations. The hybridization of SL modes results in much richer hybridization scenario in terms of wavelength and quality factor control, compared to a hybridization of LSP in a short-range configuration. It offers unprecedented opportunities to generate innovative optical devices, with high flexible tunability.

Optical Characterization of Plasmonic Indium Lattices Fabricated via Electrochemical Deposition.

The optical properties of periodic metallic nanoparticle lattices have found many exciting applications. Indium is an emerging plasmonic material that offers to extend the plasmonic applications given by gold and silver from the visible to the ultraviolet spectral range, with applications in imaging, sensing, and lasing. Due to the high vapor pressure/low melting temperature of indium, nanofabrication of ordered metallic nanoparticles is nontrivial. In this work, we show the potential of selective area electrochemical deposition to generate large-area lattices of In pillars for plasmonic applications. We study the optical response of the In lattices by means of angle-dependent extinction measurements demonstrating strong plasmonic surface lattice resonances and a good agreement with numerical simulations. The results open avenues toward high-quality lattices of plasmonic indium nanoparticles and can be extended to other promising plasmonic materials that can be electrochemically grown.

Fabrication of Centimeter-Scale Plasmonic Nanoparticle Arrays with Ultranarrow Surface Lattice Resonances.

Plasmonic surface lattice resonances (SLRs) supported by metallic nanoparticle (NP) arrays show diverse applications including nanolasers, sensors, photocatalysis, and nonlinear optics. However, to rationally fabricate high-quality plasmonic NP arrays with ultranarrow SLR line widths over large areas remains challenging. This article describes a general approach for the efficient fabrication of centimeter-scale inorganic NP arrays with precisely controlled NP size, composition, position, and lattice geometry. This method combines the processes of solvent-assisted soft lithography and in situ site-specific NP growth to reproducibly create many replicates of NP arrays without utilizing cleanroom and specialized equipment. For demonstration, we show that Au NP arrays exhibit ultranarrow SLRs with a line width of 4 nm and a quality factor of 218 toward the theoretical limit.

Energy Efficient Single Pulse Switching of [Co/Gd/Pt]N Nanodisks Using Surface Lattice Resonances.

The impact of plasmonic surface lattice resonances on the magneto-optical properties and energy absorption efficiency has been studied in arrays of [Co/Gd/Pt]N multilayer nanodisks. Varying the light wavelength, the disk diameter, and the period of the array, it is demonstrated that surface lattice resonances allow all-optical single pulse switching of [Co/Gd/Pt]N nanodisk arrays with an energy 400% smaller than the energy needed to switch a continuous [Co/Gd/Pt]N film. Moreover, the magneto-optical Faraday effect is enhanced at the resonance condition by up to 5,000%. The influence of the disk diameter and array period on the amplitude, width and position of the surface lattice resonances is in qualitative agreement with theoretical calculations and opens the way to designing magnetic metasurfaces for all-optical magnetization switching applications.

Plasmonic Surface Lattice Resonances in Suspended Symmetric Double-Layer Gratings

Surface lattice resonances (SLRs) with high-quality factors supported by metal nanoparticle arrays are useful for plasmonic nanolasers, biochemical sensors, and surface-enhanced Raman spectroscopy. Most nanoparticle arrays are fabricated on a substrate, and the refractive index mismatch between the substrate and superstrate suppresses the performance of SLRs. In this work, we propose unique SLRs excited in suspended, self-aligned symmetric double-layer gratings with index-matched environment. The self-aligned double-layer gratings are fabricated using a single-step electron beam lithography and exhibit a Fano-like spectra resulting from interference between out-of-plane plasmonic resonances and diffraction modes. By changing the incident angle and refractive index of the surrounding medium, the SLRs can be tuned from visible to near-infrared regions with a high-quality factor of 120.

Experimental and theoretical investigation of waveguided plasmonic surface lattice resonances.

Plasmonic nanostructures are good candidates for refractive index sensing applications through the surface plasmon resonance due to their strong dependence on the surrounding dielectric media. However, typically low quality-factor limits their application in sensing devices. To improve the quality-factor, we have experimentally and theoretically investigated two-dimensional gold nanoparticle gratings situated on top of a waveguide. The coupling between the localized surface plasmon and waveguide modes results in Fano-type resonances, with high quality-factors, very similar to plasmonic surface lattice resonances. By combining plasmonic surface lattice resonance and waveguide theory, we present a theoretical framework describing the structures. By immersing the fabricated samples in three different media we find a sensitivity of ∼50 nm/RIU and figure of merit of 8.9, and demonstrate good agreement with the theory presented. Further analysis show that the sensitivity is very dependent on the waveguide parameters, grating constant and the dielectric environment, and by tuning these parameters we obtain a theoretical sensitivity of 887 nm/RIU.

Theoretical study of extremely narrow plasmonic surface lattice resonances observed by MIM nanogratings under normal incidence in asymmetric environments

Nanoarray structures can support plasmonic surface lattice resonances (SLRs) with extremely narrow linewidths and huge electric field enhancement features, which are attractive applications in nanolasers, biochemical sensors, and nonlinear optics. However, current nanoarray structures located in an asymmetric dielectric environment with a refractive index contrast of 1.00/1.52 of the superstrate/substrate excite much poorer SLRs under normal incidence, which largely limits their application range. In this work, we report extremely narrow SLRs supported by one-dimensional metal–insulator–metal nanograting in asymmetric dielectric environments. The simulation results show that an SLRs with linewidth of 3.26 nm and quality factor of 233.2 can be excited under normal incidence. This high-quality SLRs is attributed to the interference formation between the out-of-plane dipole resonance mode and the out-of-plane quadrupole resonance mode. We also show that the resonance wavelength and quality factor can be tuned by changing the structure geometry and period, and we calculate the normal incidence SLRs quality factor to be up to 248 in 1.33/1.52 and 250 in 1.45/1.52. We expect the SLRs of this work to find potential applications in asymmetric dielectric environments.

Thermal Control of Plasmonic Surface Lattice Resonances.

Plasmonic metasurfaces exhibiting collective responses known as surface lattice resonances (SLRs) show potential for realizing flat photonic components for wavelength-selective processes, including lasing and optical nonlinearities. However, postfabrication tuning of SLRs remains challenging, limiting the applicability of SLR-based components. Here, we demonstrate how the properties of high quality factor SLRs are easily modified by breaking the symmetry of the nanoparticle surroundings. We break the symmetry by changing the refractive index of the overlying immersion oil by controlling the ambient temperature of the device. We show that a modest temperature change of 10 °C can increase the quality factor of the SLR from 400 to 750. Our results demonstrate accurate and reversible modification of the properties of the investigated SLRs, paving the way toward tunable SLR-based photonic devices. More generally, we show how symmetry breaking of the environment can be utilized for efficient and potentially ultrafast modification of the SLR properties.

Strong Coupling between Plasmonic Surface Lattice Resonance and Photonic Microcavity Modes

We report the strong coupling between plasmonic surface lattice resonances (SLRs) and photonic Fabry-Pérot (F-P) resonances in a microcavity embedded with two-dimensional periodic array of metal-insulator-metal nanopillars. For such a plasmonic-photonic system, we show that the SLR can be strongly coupled to the F-P resonances of both the odd- and even orders, and that the splitting energy reaches as high as 153 meV in the visible regime. Taking advantage of the strong coupling, the resulted high-energy upper polariton has similar characteristics as the plasmonic SLR, but the quality factor is almost twice of that of the SLR. We expect that this work will provide a new scheme for strong coupling between plasmonic and photonic modes, and will point to a new direction to improve the quality factor of SLRs.

Purcell Effect of Plasmonic Surface Lattice Resonances and Its Influence on Energy Transfer

Purcell Effect of Plasmonic Surface Lattice Resonances and Its Influence on Energy Transfer

Quality factor enhancement of plasmonic surface lattice resonance by using asymmetric periods

We report that using asymmetric lattice periods can enhance the quality factor of plasmonic surface lattice resonances (SLRs) in two-dimensional array of metal-insulator-metalnanopillars in asymmetric dielectric environment. Simulation results show that by adopting appropriate asymmetric lattice periods, the SLR quality factor can be enhanced by 24\\% compared with the scenario of symmetric periods. We find that the SLR quality factor is optimized when the resonance wavelength is closest to the Rayleigh cutoff wavelength. We also find that the SLRs effect is polarization sensitive in the proposed structure. We expect this work will advance the engineering of SLRs especially in asymmetric dielectric environments, and will promote their applications in sensing.

High-Q quadrupolar plasmonic lattice resonances in horizontal metal-insulator-metal gratings.

We propose a plasmonic platform for achieving out-of-plane quadrupolar plasmonic surface lattice resonances (SLRs) with large quality factors. The proposed platform is composed of a horizontal metal-insulator-metal (MIM) grating embedded in a homogeneous dielectric environment. Numerical results based on rigorous coupled-wave analysis show that under oblique incidences, high-Q out-of-plane quadrupolar SLRs can be excited at wavelengths of 1242 nm over a wide range of insulator widths, and the quality factor can reach 1036. As a comparison, under the same conditions, only dipolar SLRs with much lower quality factors of ∼300 can be excited in a vertical MIM grating, which has the same period and a quarter-turned unit cell. We expect that the proposed high-Q quadrupolar SLR platform will find applications in light-matter interactions on the nanoscale.

Effect of Ag Nanocube Optomechanical Modes on Plasmonic Surface Lattice Resonances

Noble metal nanoparticles patterned in ordered arrays can interact and generate hybrid plasmonic–photonic resonances called surface lattice resonances (SLRs). Dispersion curves help explain how the...