Mie Resonances Research Articles

Photo-thermo-optical modulation of Raman scattering from Mie-resonant silicon nanostructures

Abstract Raman scattering is sensitive to local temperature and thus offers a convenient tool for non-contact and non-destructive optical thermometry at the nanoscale. In turn, all-dielectric nanostructures, such as silicon particles, exhibit strongly enhanced photothermal heating due to Mie resonances, which leads to the strong modulation of elastic Rayleigh scattering intensity through subsequent thermo-optical effects. However, the influence of the complex photo-thermo-optical effect on inelastic Raman scattering has yet to be explored for resonant dielectric nanostructures. In this work, we experimentally demonstrate that the strong photo-thermo-optical interaction results in the nonlinear dependence of the Raman scattering signal intensity from a crystalline silicon nanoparticle via the thermal reconfiguration of the resonant response. Our results reveal a crucial role of the Mie resonance spectral sensitivity to temperature, which modifies not only the conversion of the incident light into heat but also Raman scattering efficiency. The developed comprehensive model provides the mechanism for thermal modulation of Raman scattering, shedding light on the photon–phonon interaction physics of resonant material, which is essential for the validation of Raman nanothermometry in resonant silicon structures under a strong laser field.

Silicon eccentric shell nanoparticles fabricated by template-assisted deposition for Mie magnetic resonances enhanced light confinement

We report a structure of silicon eccentric shell particles array, fabricated by the SiO2 particles monolayer array assisted deposition of amorphous Si, for high-efficiency light confinement. The SiO2 particles monolayer array is tailored to regulate its interparticle distance, followed by silicon film deposition to obtain silicon eccentric shell arrays with positive and negative off-center distance e. We studied the Mie resonances of silicon solid sphere, concentric shell, eccentric shell and observed that the eccentric shell with positive off-center e supports superior light confinement because of the enhanced Mie magnetic resonances. Spectroscopic measurements and finite difference time domain simulations were conducted to examine the optical performance of the eccentric shell particles array. Results show that the Mie magnetic resonance wavelength can be easily regulated by the size of the inner void of the silicon shell to realize tunable enhanced light confinement. It was found silicon shell with D = 460/520 nm offered high enhanced light absorption efficiency at wavelength of λ = 830 nm, almost beyond the bandgap of the amorphous silicon.

Dielectric‐Based Metamaterials for Near‐Perfect Light Absorption

AbstractThe emergence of metamaterials and their continued prosperity have built a powerful working platform for accurately manipulating the behavior of electromagnetic waves, providing sufficient possibility for the realization of metamaterial absorbers with outstanding performance. However, metamaterial absorbers composed of metallic materials typically possess many unfavorable factors, such as non‐adjustable absorption, easy oxidation, low‐melting, and expensive preparation costs. The selection of dielectric materials provides excellent alternatives due to their remarkable properties, thus dielectric‐based metamaterial absorbers (DBMAs) have attracted much attention. To promote breakthroughs in DBMAs and guide their future development, this work systematically and deeply reviews the recent research progress of DBMAs from four different but progressive aspects, including physical principles; classifications, material selections and tunable properties; preparation technologies; and functional applications. Five different types of theories and related physical mechanisms, such as Mie resonance, guided‐mode resonance, and Anapole resonance, are briefly outlined to explain DBMAs having near‐perfect absorption performance. Mainstream material selections, structure designs, and different types of tunable DBMAs are highlighted. Several widely utilized preparation methods for customizing DBMAs are given. Various practical applications of DBMAs in sensing, stealth technology, solar energy absorption, and electromagnetic interference suppression are reviewed. Finally, some key challenges and feasible solutions for DBMAs’ future development are provided.

Resonance-enhanced photoemission from GaInAsSb nanopillar array photocathodes

A resonance-enhanced GaInAsSb nanopillar array negative electron affinity potential photocathode based on Mie resonance excitation at infrared wavelengths can significantly enhance the absorption and quantum efficiency of nanopillar arrays. Our study indicates the different periodic structures have very little effect on the QE for the nanopillar arrays. However, the smaller the period of the array, the higher the quantum efficiency is achieved, but the probability of being collected by the anode is reduced, so a compromise should be considered in the structure design. Moreover, the incident light inclination and the external electric field can significantly affect the quantum efficiency of the nanopillar arrays. The photocathodes studied here have a quantum efficiency of over 5.7% with an angle of incidence of 30∘ and an applied electric field intensity of 1.2[Formula: see text]V/[Formula: see text]m. This work provides an important reference and theoretical basis for the design and optimization of resonance-enhanced GaInAsSb nanopillar arrays photocathode.

Macroscale TiO2 Microspherical Arrays with Multiple Synergistic Effect for Highly Sensitive Surface‐Enhanced Raman Scattering

AbstractSemiconductor materials represent an ideal choice for designing surface‐enhanced Raman scattering (SERS)‐based sensors due to their superior thermal and chemical stability compared to conventional metal materials. However, current SERS‐active semiconductor substrates have limitations such as low detection sensitivity and often complicated preparation steps, which restrict their real‐life applications. In this work, for the first time the feasibility of large‐area fabricating SERS‐active semiconductor substrates based on screen‐printing of micron‐sized TiO2 ink synthesized through a simple flame thermal‐assisted method is demonstrated. The resultant TiO2 microspherical arrays (MSAs) exhibit extraordinary SERS sensitivity with an enhancement factor of 3.28 × 107, which represents one of the highest sensitivity and are the easiest strategy among the reported SERS‐active semiconductor substrates. Both experiments and simulations rationalize the observed enhancement factor and propose that multiple synergistic resonances, including Mie resonance, charge‐transfer resonance, and molecular resonance significantly boost the performance of semiconductor substrates. Dye‐modified TiO2 MSAs are further exploited as the sensing platform for the development of a ratiometric SERS sensor, enabling the highly sensitive, selective, low cost, and stable detection of Hg2+ ions. This study opens up new possibilities for preparing a large‐scale SERS‐active semiconductor array, ultimately advancing the fields of semiconductor‐based SERS sensing technology.

Revisiting anapoles in a single high-index dielectric structure

High-index dielectric structures support electric and magnetic Mie resonance. Through careful manipulation of geometric parameters, destructive interference can be induced between electric multipole moments and toroidal multipole moments. This leads to the formation of anapoles, which are characterized by quenched scattering in the far field and giant enhancement in the near field. Here, we revisit the formation mechanism of anapole states in a single dielectric structure with a high refractive index from an eigenmode perspective. We find that scattering efficiency is mainly determined by the intrinsic phase governed by the leaky mode of the structure and the extrinsic phase induced by the frequency deviation from resonance. It is also demonstrated that the anapole modes in a two-dimensional cylinder and a three-dimensional sphere can only occur in the following two situations: (1) when only one mode is involved, the combined phase of intrinsic and extrinsic phase should be equal to 2π at a certain frequency (anapole frequency), which is very close to the resonance frequency. Generally, these types of anapoles are low-order anapoles since low-order resonant modes (i.e., magnetic (electric) dipole and quadrupole) are well separated. (2) If two or more leaky modes are involved, the combined phase for each mode must be 2π at the same frequency located between the two resonances. This corresponds to the high-order anapoles. It is also found that more anapole states will emerge with increasing refractive index. Our results may provide new perspectives for designing high-order anapoles with more freedom.

Dielectric‐Metasurface‐Enhanced Kerr Self‐Modulation for Passively Q‐Switching

AbstractDielectric metasurfaces are highly sought‐after since they have found a variety of linear and nonlinear applications. Here, a novel transmission modulation is presented for pulsed laser generation by directly exploiting the enhanced Kerr effect from a periodic array of silicon nanodisks. The Mie resonance of the unit cells enhances the Kerr effect of the silicon material and is redshifted by the latter, so that the transmission of the metasurface at the working wavelength is strongly modulated (the observed modulation depth is above 3% under moderate exciting power). By inserting the fabricated metasurface as a self‐modulator into a ring cavity fiber laser, stable Q‐switched pulse laser output is achieved with a duration of 1.4 µs and a repetition rate of 60 kHz. This work opens a door for ultra‐thin low‐loss dielectric metasurfaces to efficiently shape the operation of pulsed lasing based on their enhanced nonlinear effects and flexible propagation manipulation.

Realizing Minimally Perturbed, Nonlocal Chiral Metasurfaces for Direct Stokes Parameter Detection.

Recent development in nonlocal resonance based chiral metasurfaces draws great attention due to their abilities to strongly interact with circularly polarized light at a relatively narrow spectral bandwidth. However, there still remain challenges in realizing effective nonlocal chiral metasurfaces in optical frequency due to demanding fabrications such as 3D-multilayered or nanoscaled chiral geometry, which, in particular, limit their applications to polarimetric detection with high-Q spectra. Here, we study the underlying working principles and reveal the important role of the interaction between high-Q nonlocal resonance and low-Q localized Mie resonance in realizing effective nonlocal chiral metasurfaces. Based on the working principles, we demonstrate one of the simplest types of nonlocal chiral metasurfaces which directly detects a set of Stokes parameters without the numerical combination of transmitted values presented from typical Stokes metasurfaces. This is achieved by minimally altering the geometry and filling ratio of every constituent nanostructure in a unit cell, facilitating consistent-sized nanolithography for all samples experimentally at a targeted wavelength with relatively high-Q spectra. This work provides an alternative design rule to realizing effective polarimetric metasurfaces and the potential applications of nonlocal Stokes parameters detection.

Dirac hierarchy in confined Mie resonance photonic crystals

Dirac hierarchy in confined Mie resonance photonic crystals

Efficient Third Harmonic Generation from Magnetic Resonance in Low-Index Dielectric Nanopillars

Boosting the harmonic generation of light in nanostructures through efficiently enhancing the light–matter interaction has received enormous attention and applications. Low-index dielectric nanoparticles, as one of the crucial members of nanophotonics, have not been successful in nonlinear enhancement due to weak Mie resonance and poor light confinement. Here, we designed efficient third harmonic generation (THG) in low-index dielectric nanopillars sandwiched by double layers of metal dressing (Au/polymer/Au), where the polymer offers essential nonlinear susceptibility. The resonance of the low-index nanopillars significantly enhanced the scattering and had a strong magnetic response that could boost the THG effect. We predict that the THG efficiency reaches up to 3 × 10−6 (six orders of enhancement) at a third harmonic wavelength of 300 nm. The efficient THG in low-index dielectric nanopillars may open the possibility for the development of a new type of efficient nonlinear coherent source.

Mie-Resonant Nanophotonic-Enhancement of Asymmetry in Sodium Chlorate Chiral Crystallization.

Studies on chiral spectroscopy have recently demonstrated strong enhancement of chiral light-matter interaction in the chiral near-field of Mie resonance in high-refractive-index dielectric nanostructures by studies on chiral spectroscopy. This situation has motivated researchers to demonstrate effective chiral photosynthesis under a chiral near-field beyond circularly polarized light (CPL) as a chiral source. However, the effectivity of the chiral near-field of Mie resonance for chiral photosynthesis has not been clearly demonstrated. One major challenge is the experimental difficulty in evaluating enantiomeric excess of a trace amount of chiral products synthesized in the near-field. Here, by adopting sodium chlorate chiral crystallization as a phenomenon that includes both synthesis and the amplification of chiral products, we show that crystallization on a Mie-resonant silicon metasurface excited by CPL yields a statistically significant large crystal enantiomeric excess of ∼18%, which cannot be achieved merely by CPL. This result provides implications for efficient chiral photosynthesis in a chiral near-field.

Enhancing Scattering Circular Dichroism of Chiral Substrate via Mie Resonances

Enhancing Scattering Circular Dichroism of Chiral Substrate via Mie Resonances

Self-hybridisation between interband transitions and Mie modes in dielectric nanoparticles

Abstract We discuss the possibility of self-hybridisation in high-index dielectric nanoparticles, where Mie modes of electric or magnetic type can couple to the interband transitions of the material, leading to spectral anticrossings. Starting with an idealised system described by moderately high constant permittivity with a narrow Lorentzian, in which self-hybridisation is visible for both plane-wave and electron-beam excitation, we embark on a quest for realistic systems where this effect should be visible. We explore a variety of spherical particles made of traditional semiconductors such as Si, GaAs, and GaP. With the effect hardly discernible, we identify two major causes hindering observation of self-hybridisation: the very broad spectral fingerprints of interband transitions in most candidate materials, and the significant overlap between electric and magnetic Mie modes in nanospheres. We thus depart from the spherical shape, and show that interband–Mie hybridisation is indeed feasible in the example of GaAs cylinders, even with a simple plane-wave source. This so-far unreported kind of polariton has to be considered when interpreting experimental spectra of Mie-resonant nanoparticles and assigning modal characters to specific features. On the other hand, it has the potential to be useful for the characterisation of the optical properties of dielectric materials, through control of the hybridisation strength via nanoparticle size and shape, and for applications that exploit Mie resonances in metamaterials, highly-directional antennas, or photovoltaics.

Transverse Magneto-Optical Kerr Effect Enhancement in Si–Ni Nanogratings by Mie and Surface Lattice Resonances

Transverse Magneto-Optical Kerr Effect Enhancement in Si–Ni Nanogratings by Mie and Surface Lattice Resonances

Dielectric particle trimer: enhanced sensing of environmental changes through coupled Mie resonances

Dielectric particle trimer: enhanced sensing of environmental changes through coupled Mie resonances

Disentangled Higher‐Orbital Bands and Chiral Symmetric Topology in Confined Mie Resonance Photonic Crystals (Laser Photonics Rev. 18(2)/2024)

Disentangled Higher‐Orbital Bands and Chiral Symmetric Topology in Confined Mie Resonance Photonic Crystals (Laser Photonics Rev. 18(2)/2024)

1D Sb2S3 with Strong Mie Resonance Toward Highly‐Sensitive Polarization‐Discriminating Photodetection and Its Application in High‐Temperature‐Proof Imaging and Dual‐Channel Communications (Advanced Optical Materials 5/2024)

1D Sb₂S₃ with Strong Mie Resonance Toward Highly‐Sensitive Polarization‐Discriminating Photodetection and Its Application in High‐Temperature‐Proof Imaging and Dual‐Channel Communications (Advanced Optical Materials 5/2024)

Enhancement of Photoluminescence Properties via Polymer Infiltration in a Colloidal Photonic Glass

Photonic glasses (PGs) based on the self-assembly of monosized nanoparticles can be an effective tool for realizing disordered structures capable of tailoring light diffusion due to the establishment of Mie resonances. In particular, the wavelength position of these resonances depends mainly on the morphology (dimension) and optical properties (refractive index) of the building blocks. In this study, we report the fabrication and optical characterization of photonic glasses obtained via a self-assembling technique. Furthermore, we have demonstrated that the infiltration of these systems with a green-emitting polymer enhances the properties of the polymer, resulting in a large increase in its photoluminescence quantum yield and a 3 ps growing time of the photoluminescence time decay Finally, the development of the aforementioned system can serve as a suitable low-cost platform for the realization of lasers and fluorescence-based bio-sensors.

A new hybrid metamaterial absorber composed of ceramic resonators stacked on thin conductive rubber layer

In this letter, a hybrid metamaterial absorber made of ceramic resonators stacked on the traditional thin conductive rubber layer (RAT) has been developed. While RAT has been proven to be an effective absorber with good absorption around 10.5 GHz, its ability to absorb electromagnetic (EM) waves is inconsistent due to its flexible characteristic. Meanwhile, the absorption bandwidth above 90 % for RAT is constrained by its dispersion, limiting the coverage across the entire X-band (8–12 GHz). To address these limitations, we have incorporated the ceramic artificial nanostructure to enhance absorption intensity and broaden the absorption bandwidth by leveraging the strong magnetic Mie resonance of the ceramic resonator. Simultaneously, the number of absorption peaks and the bandwidth of each absorption peak can be controlled by adjusting the offset distance of the ceramic resonators and by varying the sintering temperature of the ceramics. Through the integration of metamaterial design and ceramic materials optimization, we have experimentally demonstrated the feasibility of multi-band, high-absorption devices by utilizing the hybrid structure of ceramic resonators and RAT, which opens up new possibilities for the further development of absorber devices.

Tuning the spectrum of near-field radiative heat transfer using Mie resonance based metamaterials

Tuning the spectrum of near-field radiative heat transfer using Mie resonance based metamaterials