Esculetin improves murine mastitis induced by streptococcus isolated from bovine mammary glands by inhibiting NF-κB and MAPK signaling pathways.

Cow mastitis, caused by Streptococcus infection of the mammary glands, is a common clinical disease that can lead to decreased milk quality and threaten animal welfare and performance. Esculetin (ESC) is a coumarin with anti-inflammatory and anti-asthmatic effects. However, whether ESC has therapeutic effects on mastitis remains unexplored.

Forsythoside A regulates autophagy and apoptosis through the AMPK/mTOR/ULK1 pathway and alleviates inflammatory damage in MAC-T cells.

Dairy cow mastitis is the most common disease encountered in dairy farming. Lipopolysaccharides (LPS), among the major virulence-related factors produced by Escherichia coli, stimulate mammary gland inflammation and cause its damage, thereby affecting milk yield and quality. Forsythoside A (FTA) is among the main active components of forsythia.

Synthesis of Au/CdSe Janus Nanoparticles with Efficient Charge Transfer for Improving Photocatalytic Hydrogen Generation.

Metal-semiconductor heterostructures integrate multiply functionalities beyond those of their individual counterparts. Great efforts have been devoted to synthesize heterostructures with controlled morphologies for the applications ranging from photocatalysis to photonic nanodevices. Beyond the morphologies, the interface between two counterparts also significantly influences the performance of the heterostructures.

Manipulating the fluorescence of exciton-plasmon hybrids in the strong coupling regime with dual resonance enhancements.

Strong couplings between molecular excitons and metal plasmons bring advantages to effectively manipulate the optical properties of hybrid systems, including both absorption and fluorescence. In contrast to absorption behaviours, which have been quite well understood and can be categorized into different regimes such as Fano dip and Rabi splitting, the characteristics of fluorescence in strongly coupled hybrids remain largely unexplored. Quenching instead of the enhancement of fluorescence is usually observed in the corresponding experiments, and a theoretical model to deal with this phenomenon is still lacking.

Highly tunable nonlinear response of Au@WS hybrids with plasmon resonance and anti-Stokes effect.

We synthesize Au@WS2 hybrid nanobelts and investigate their third-order nonlinear responses mediated by a strong anti-Stokes effect. By using the femtosecond Z-scan technique and tuning the excitation photon energy (Eexc), we find the sign reversals of both nonlinear absorption coefficient β and nonlinear refractive index γ to be around 1.60 eV, which is prominently higher than the bandgap (1.

Pure magnetic-quadrupole scattering and efficient second-harmonic generation from plasmon-dielectric hybrid nano-antennas.

We theoretically demonstrate that pure magnetic quadrupole (MQ) scattering is achieved via the excitation of anapole modes and Fano resonance in noble metal (Au or Ag) and high refractive index dielectric (AlGaAs) hybrid nano-antennas. In Au-AlGaAs hybrid nano-antennas, electric anapole and magnetic anapole modes are observed, leading to the suppressions of electric and magnetic dipoles. Introducing gain material to AlGaAs nanodisk to increase the strength of electric quadrupole (EQ) Fano resonance leads to the suppression of EQ scattering.

Enhanced Second Harmonic Generation by Mode Matching in Gain-assisted Double-plasmonic Resonance Nanostructure.

We theoretically study the gain-assisted double plasmonic resonances to enhance second harmonic generation (SHG) in a centrosymmetric multilayered silver-dielectric-gold-dielectric (SDGD) nanostructure. Introducing gain media into the dielectric layers can not only compensate the dissipation and lead to giant amplification of surface plasmons (SPs), but also excite local quadrupolar plasmon which can boost SHG by mode matching. Specifically, as the quadrupolar mode dominates SHG in our nanostructure, under the mode matching condition, the intensity of second harmonic near-field can be enhanced by 4.

Magnetic Fano resonance-induced second-harmonic generation enhancement in plasmonic metamolecule rings.

The "artificial magnetic" resonance in plasmonic metamolecules extends the potential application of magnetic resonance from terahertz to optical frequency bypassing the problem of magnetic response saturation by replacing the conduction current with the ring displacement current. So far, the magnetic Fano resonance-induced nonlinearity enhancement in plasmonic metamolecule rings has not been reported. Here, we use the magnetic Fano resonance to enhance second-harmonic generation (SHG) in plasmonic metamolecule rings.

Plasmon-assisted site-selective growth of Ag nanotriangles and Ag-CuO hybrids.

We report a plasmon-assisted growth of metal and semiconductor onto the tips of Ag nanotriangles (AgNTs) under light irradiation. The site-selective growth of Ag onto AgNTs are firstly demonstrated on the copper grids and amine-coated glass slides. As the irradiation time increases, microscopic images indicate that AgNTs gradually touch with each other and finally "weld" tip-to-tip together into the branched chains.

Plasmon-Modulated Excitation-Dependent Fluorescence from Activated CTAB Molecules Strongly Coupled to Gold Nanoparticles.

Excitation-dependent fluorophores (EDFs) have been attracted increasing attention owing to their high tunability of emissions and prospective applications ranging from multicolor patterning to bio-imaging. Here, we report tunable fluorescence with quenching dip induced by strong coupling of exciton and plasmon in the hybrid nanostructure of CTAB* EDFs and gold nanoparticles (AuNPs). The quenching dip in the fluorescence spectrum is tuned by adjusting excitation wavelength as well as plasmon resonance and concentration of AuNPs.

Transport properties of a single plasmon interacting with a hybrid exciton of a metal nanoparticle-semiconductor quantum dot system coupled to a plasmonic waveguide.

The transport properties of a single plasmon interacting with a hybrid system composed of a semiconductor quantum dot (SQD) and a metal nanoparticle (MNP) coupled to a one-dimensional surface plasmonic waveguide are investigated theoretically via the real-space approach. We considered that the MNP-SQD interaction leads to the formation of a hybrid exciton and the transmission and reflection of a single incident plasmon could be controlled by adjusting the frequency of the classical control field applied to the MNP-SQD hybrid nanosystem, the kinds of MNPs and the background media. The transport properties of a single plasmon interacting with such a hybrid nanosystem discussed here could find applications in the design of next-generation quantum devices, such as single-photon switching and nanomirrors, and in quantum information processing.

Plasmonic phase modulator based on novel loss-overcompensated coupling between nanoresonator and waveguide.

We present that surface plasmon polariton, side-coupled to a gain-assisted nanoresonator where the absorption is overcompensated, exhibits a prominent phase shift up to π maintaining the flat unity transmission across the whole broad spectra. Bandwidth of this plasmonic phase shift can be controlled by adjusting the distance between the plasmonic waveguide and the nanoresonator. For a moderate distance, within bandwidth of 100 GHz, the phase shift and transmission are constantly maintained.

Tunable plasmon resonance and enhanced second harmonic generation and upconverted fluorescence of hemispheric-like silver core/shell islands.

We investigate tunable plasmon resonance and enhanced second harmonic generation (SHG) and up-converted fluorescence (UCF) of the hemispheric-like silver core/shell islands. The Ag, Ag/Ag2O, and Ag/Ag2O/Ag island films are prepared by using a sputtering technique. The SHG and UCF of the Ag/Ag2O/Ag core/shell islands near the percolating regime is enhanced 2.

Largely enhanced saturable absorption of a complex of plasmonic and molecular-like au nanocrystals.

A saturable absorber is a nonlinear functional material widely used in laser and photonic nanodevices. Metallic nanostructures have prominent saturable absorption (SA) at the plasmon resonance frequency owing to largely enhanced ground state absorption. However, the SA of plasmonic metal nanostructures is hampered by excited-state absorption processes at very high excitation power, which usually leads to a changeover from SA to reversed SA (SA→RSA).

Synthesis and enhanced fluorescence of Ag doped CdTe semiconductor quantum dots.

Doping with intentional impurities is an intriguing way to tune the properties of semiconductor nanocrystals. However, the synthesis of some specific doped semiconductor nanocrystals remains a challenge and the doping mechanism in this strongly confined system is still not clearly understood. In this work, we report, for the first time, the synthesis of stable and water-soluble Ag-doped CdTe semiconductor quantum dots (SQDs) via a facile aqueous approach.

Plasmonic nanorod arrays of a two-segment dimer and a coaxial cable with 1 nm gap for large field confinement and enhancement.

Seeking plasmonic nanostructures with large field confinement and enhancement is significant for photonic and electronic nanodevices with high sensitivity, reproducibility, and tunability. Here, we report the synthesis of plasmonic arrays composed of two-segment dimer nanorods and coaxial cable nanorods with ∼1 nm gap insulated by a self-assembled Raman molecule monolayer. The gap-induced plasmon coupling generates an intense field in the gap region of the dimer junction and the cable interlayer.

Plasmonic Fano resonances in metallic nanorod complexes.

Plasmonic Fano resonances (FRs) in nanostructures have been extensively studied in recent years. Nanorod-based complexes for FRs have also attracted much attention. The basic optical properties and fabrication technology of different kinds of plasmonic nanorods have been greatly developed over the last several years.

Plasmon-enhanced light harvesting of chlorophylls on near-percolating silver films via one-photon anti-Stokes upconversion.

There exists a wealth of means of efficient utilization of solar energy in nature, with photosynthesis of chlorophylls as a prime example. Separately, artificially structured plasmonic materials are versatile in light harvesting and energy conversion. Using a simple and scalable design of near-percolating silver nanostructures, we demonstrate that the light-harvesting efficiency of chlorophylls can be drastically enhanced by tuning the plasmon frequency of the constituent silver nanoparticles to coincide with the maximal photon flux of sunlight.

Solution-dispersible Au nanocube dimers with greatly enhanced two-photon luminescence and SERS.

We report the synthesis of 43-nm diameter Au nanocube dimers by using Ag(+) ions as competitive ligands to freeze L-cysteine-induced assembly process of the nanocubes to a desirable stage. Ascribed to the resonant interparticle coupling with an newly arising plasmon band at 710 nm and local field enhancement, the two-photon luminescence intensity of the Au nanocube dimers in solution was over 20 times stronger than that of the monomers in the wavelength range 555-620 nm. Furthermore, by coupling Raman tags onto the nanocube surface, a solution-based surface-enhanced Raman scattering (SERS) of the nanocube dimers had an enhancement factor of over 10 times compared to the isolated nanocubes.

Silica-coated and annealed CdS nanowires with enhanced photoluminescence.

The CdS/SiO(2) core/shell nanowires (NWs) with controlled shell thickness were successfully synthesized and subsequently heat-treated at 500 °C. The influences of silica shell coating and annealing processes on their optical properties have been investigated. Compared with original CdS NWs, the annealed CdS/SiO(2) NWs exhibited an enhanced band-edge emission with slowed photoluminescence lifetime, while the intensity of defect emission decreased.

Strong bonding magnetic plasmon hybridizations in double split-ring resonators.

The complex magnetic dipole plasmon couplings in double split-ring resonators are investigated. Two split peaks in the absorption spectrum of these coupled systems are observed, but even the shorter-wavelength resonance peak can be redshifted compared to the peaks of individual rings. The magnetic plasmon fields outside rings are found to play an important role in these strong couplings.

Optical bistability and nonlinearity of coherently coupled exciton-plasmon systems.

We theoretically investigated optical third-order nonlinearity of a coherently coupled exciton-plasmon hybrid system under a strong control field with a weak probe field. The analytic formulas of exciton population and effective third-order optical susceptibility of the hybrid of a metal nanoparticle (MNP) and a semiconductor quantum dot (SQD) were deduced. The bistable exciton population and the induced bistable nonlinear absorption and refraction response were revealed.

Dynamically tuning emission band of CdSe/ZnS quantum dots assembled on Ag nanorod array: plasmon-enhanced Stark shift.

We demonstrate tuning emission band of CdSe/ZnS semiconductor quantum dots (SQDs) closely-packed in the proximity of Ag nanorod array by dynamically adjusting exciton-plasmon interaction. Large red-shift is observed in two-photon luminescence (TPL) spectra of the SQDs when the longitudinal surface plasmon resonance (LSPR) of Ag nanorod array is adjusted to close to excitation laser wavelength, and the spectral red-shift of TPL reaches as large as 101 meV by increasing excitation power, which is slightly larger than full width at half-maximum of emission spectrum of the SQDs. The observed LSPR-dependent spectral shifting behaviors are explained by a theoretical model of plasmon-enhanced quantum-confined Stark effect.