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Light therapy has become the subject of research on cancer treatment because of its selectivity, low invasive damage, and side effects. Photothermal therapy (PTT) and photodynamic therapy (PDT) are prevalent treatments used to induce cancer cell apoptosis by generating heat and reactive oxygen species (ROS). In this study, mesoporous silica shell-coated gold nanorods (AuNR@mS) are synthesized by seed crystal growth method. AuNR@mS are assembled into nanocomposites through electrostatic adsorption with lanthanide-doped upconversion nanoparticles (UCNP). When controlling the aspect ratio of gold nanorods (AuNRs), the surface plasmon resonance peaks of the short-axis and the long-axis match the maximum absorption cross section at 520 and 660 nm of the fluorescence light released by the UCNPs. The converted fluorescence stimulates AuNRs to generate heat through energy transfer. ROS production is induced by loading the photosensitizer Merocyanine 540 (MC540) in the mesoporous silica layer and is further enhanced through the surface plasma resonance effect of the AuNRs. This novel nanoplatform combines PTT and PDT in a single 808 nm near-infrared synergistic light therapy.

Integrated‐resonant units (IRUs), incorporated with multiple resonators into one building block or one resonator with multiple modes, show a great capacity for achieving controllable smooth and linear phase dispersion as well as amplitude manipulation over a continuous and broad bandwidth. Based on an IRU library designed in the wavelength range of 400 to 667 nm, three achromatic deflectors showing constant steering angles of 9.5°, 19°, and 28°, respectively, are numerically validated. Achromatic metalenses with various numerical aperture (NA) values are further experimentally demonstrated, displaying an unvaried focal length throughout the bandwidth of 420–650 nm (≈50% bandwidth to the central wavelength). The focusing efficiency of the achromatic metalens with NA = 0.124 achieves 26.31%, 19.71%, and 20.37%, respectively, at wavelengths of 420, 550, and 650 nm. In addition, a multi‐nanorod IRU design is numerically optimized to achieve above 50% conversion efficiency from visible to near‐infrared (400–1400 nm). Such IRU design is then employed to construct a versatile polarization convertor, generating six different polarization states simultaneously upon one linear‐polarized illumination. The IRU approach with broadband control of amplitude and phase response provides an unprecedented platform in realizing multifunctional full‐color metadevices.

Twisted photon, associated with orbital angular momentum (OAM), is a physical notion that has long captivated the intriguing imagination and wide applications. Owing to the native orthogonality between different topological charges of the vortices, it will be of significant value to generate, access, and discriminate the vortex on integrated chips. Archimedean spirals or multiple split gratings are commonly employed to generate OAMs on plasmonic films. However, the single‐crystalline plasmonic surface sets a very stringent condition of probing the on‐chip OAM dynamics at sub‐femtosecond scale. In previous reports, spins of the incident light and actual topological charge of the on‐chip OAM generator are also hybridized due to the intrinsic spin‐to‐orbital angular momentum conversion, making the direct discrimination of plasmonic vortex impossible. Here, a paradigm of generating twisted surface plasmons is presented in a fully spin‐controlled fashion. With the two‐photon photoemission electron microscopy, the dynamics of OAM formation is demonstrated at subwavelength spatial resolution and sub‐femtosecond temporal resolution simultaneously, revealing its OAM‐dependent angular velocity. In addition, this scheme of twisting on‐chip plasmons shows that the challenging crystalline requirement of the thin film can be significantly alleviated. The results open up a distinct way to multiplex, record, and read the information with plasmons.

inducing electromagnetic fields. [9,10] In general, SHG conversion efficiency relies on several factors: inversion asymmetry of the hosting media, spatial overlap of the fundamental and second-harmonic (SH) modes, quality factor (Q-factor) of the involved modes, and the field intensity of the fundamental resonant mode. [11][12][13][14][15][16] Among these factors, plasmonic nanostructures [17][18][19][20][21][22][23] have a clear advantage of being particularly effective in inducing strong electromagnetic field that can increase the SHG conversion efficiency. For instance, the large field confinement associated with the magnetic resonances of split-ring resonators (SRRs) has led to a significant SHG enhancement. [23][24][25][26][27][28] While these prior results have been a major step forward in demonstrating SHG in plasmonic structures, further improvement is needed if they were to become a competitive alternative. Take SRR metasurface as an example, most of fabricated SRRs are of planar subwavelength structures, in which they lay flat on a high index dielectric substrate as illustrated in the inset of Figure 1a. While such planar SRRs (PSRRs) are relatively easy to fabricate, the strong fields present in PSRR gaps are inevitably exposed to the underlying substrate, resulting in leakage of the electromagnetic energy into the substrate, reducing the exposure of enhancedThe second harmonic generation (SHG) of vertical and planar split-ring resonators (SRRs) that are broken centro-symmetry configurations at the interface of metal surface and air is investigated. Strong interactions, better electromagnetic field confinements, and less leakage into the substrate for vertical SRRs are found. Experimental results show a 2.6-fold enhancement of SHG nonlinearity, which is in good agreement with simulations and calculations. Demonstrations of 3D metastructures and vertical SRRs with strong SHG nonlinearity majorly result from magnetic dipole and electric quadrupole clearly provides potential applications for photonics and sensing. StereometamaterialsSince its discovery soon after the invention of the laser, the second harmonic generation (SHG) as a prominent nonlinear optical effect has played an important role in various photonic applications ranging from light source, [1] high-resolution imaging, to spectroscopy. [2][3][4] Fundamentally, SHG is prohibited in bulk noble metals such as gold and silver occasionally used in metamaterials because of their centrosymmetric crystal lattices. Recently, the phenomenon of SHG has been widely studied in various metallic nanostructures, such as nanorods, nanoparticles, multiresonant, nanoantennas, etc. [5][6][7][8] In plasmonic systems, nonlinearity was mainly attributed to either the broken centro-symmetry at the metal surface or to the high degree of the asymmetric spatial variation of the

We report the most recent advances in optical meta-devices and their applications. The general principle and method of optical meta-devices are introduced. The development of the two most recent and state-of-the-art optical meta-devices, a broadband achromatic optical meta-lens in the visible range and a 60 × 60 achromatic meta-lens array, is shown. Full-color achromatic imaging in visible frequency (400 nm to 660 nm) is demonstrated with high efficiency (maximum 67%, average around 40%) by a GaN achromatic meta-lens. A nature-inspired 60 × 60 GaN achromatic meta-lens array with an individual meta-lens diameter of 21.65 μm, a focal length of 49 μm, and a numerical aperture of 0.2157 shows high-dimensional light-field image capture including the depth and velocity of the imaging objects. The total number of nano-antennas of the meta-lens array is more than 33 million which covers an area of 1.2 × 1.2 mm2. Results show the important advantages of optical meta-devices for flat optics are their small size, light weight, high efficiency, lower energy consumption, and mass producibility by semiconductor processes.

There is evidence that copper is bound to amyloid-β peptide (Aβ) in senile plaque of Alzheimer's disease. Copper also plays a role in the neurotoxicity of the Aβ aggregates associated with free radical damage. In this study, we used L-histidyl-L-histidine peptide (di-histidine) to represent Aβ along with ab initio calculation to characterize the probable coordination between Cu(II) and Aβs to explore the Aβ aggregate structures. Sixteen models of copper-di-histidine complexes were proposed to investigate the copper-induced aggregation of Aβs through copper ionic coordination. All structures of the proposed models were optimized at the M05-2X/LanL2DZ level, and an Aβ aggregation formation mechanism was proposed

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