Lithium niobate thin film electro-optic modulator.

The linear electro-optic effect offers a valuable means to control light properties via an external electric field. Lithium niobate (LN), with its high electro-optic coefficients and broad optical transparency ranges, stands out as a prominent material for efficient electro-optic modulators. The recent advent of lithium niobate-on-insulator (LNOI) wafers has sparked renewed interest in LN for compact photonic devices.

Comprehensive characterization of Epimedium-Rhizoma drynariae herb pair in rat plasma, urine, and feces metabolic profiles by UHPLC-Q-Orbitrap HRMS combined with diagnostic extraction strategy and multicomponent pharmacokinetic study by UHPLC-MS/MS.

Epimedium-Rhizoma drynariae (EP-RD) was a well-known herb commonly used to treat bone diseases in traditional Chinese medicine. Nevertheless, there was incomplete pharmacokinetic behavior, metabolic conversion and chemical characterization of EP-RD in vivo. Therefore, this study aimed to establish metabolic profiles combined with multicomponent pharmacokinetics to reveal the in vivo behavior of EP-RD.

Integrated untargeted and targeted testicular metabolomics to reveal the regulated mechanism of Gushudan on the hypothalamic-pituitary-gonadal axis of kidney-yang-deficiency-syndrome rats.

Modern studies have shown that neuroendocrine disorders caused by the dysfunction of the hypothalamic-pituitary-gonadal (HPG) axis are one of the important pathogenetic mechanisms of kidney-yang-deficiency-syndrome (KYDS). The preventive effect of Gushudan on KYDS has been reported, but its regulatory mechanisms on the HPG axis have not been elucidated. In this study, we developed an integrated untargeted and targeted metabolomics analysis strategy to investigate the regulatory mechanism of Gushudan on the HPG axis in rats with KYDS.

Chemoselectivity Strategy Based on B-Label Integrated with Tailored COF for Targeted Metabolomic Analysis of Short-Chain Fatty Acids by UHPLC-MS/MS.

Chemoselective extraction strategy is an emerging and powerful means for targeted metabolomics analysis, which allows for the selective identification of biomarkers. Short-chain fatty acids (SCFAs) as functional metabolites for many diseases pose challenges in qualitative and quantitative analyses due to their high polarity and uneven abundance. In our study, we proposed the B-labeled method for the derivatization of SCFAs using easily available 3-aminobenzeneboronic acid as the derivatization reagent, which enables the introduction of recognition unit (boric acid groups).

Integrated UHPLC-MS untargeted metabolomics and gut microbe metabolism pathway-targeted metabolomics to reveal the prevention mechanism of Gushudan on kidney-yang-deficiency-syndrome rats.

Gushudan (GSD) was a traditional Chinese prescription with the remarkable effect of kidney-tonifying and bone-strengthening. However, the potential prevention mechanisms of the GSD on kidney-yang-deficiency-syndrome (KYDS) and its regulation on gut microbe metabolism still need to be further systematically investigated. This study established untargeted urinary metabolomics based on RP/HILIC-UHPLC-Q-Orbitrap HRMS and combined with multivariate statistical analysis to discover differential metabolites and key metabolic pathways.

Topological super-modes engineering with acoustic graphene plasmons.

Acoustic graphene plasmons (AGPs) in a graphene-dielectric-metal structure possess extreme field localization and low loss, which have promising applications in strong photon-matter interaction and integrated photonic devices. Here, we propose two kinds of one-dimensional crystals supporting propagating AGPs with different topological properties, which is confirmed by the Zak phase calculations and the electric field symmetry analysis. Moreover, by combining these two plasmonic crystals to form a superlattice system, the super-modes exist because of the coupling between isolated topological interface states.

Error analysis of a rotating-metasurface polarimeter.

Polarimeters, which measure the polarization states of light directly, are essentially desired in many areas of science and technology. In our previous work, we have constructed a polarimeter based on a rotating-metasurface, and the polarization Stokes parameters of the light were measured with the known Mueller elements of the metasurface. Here, we further perform the error analysis of the metasurface polarimeter.

Giant Second Harmonic Generation from Membrane Metasurfaces.

Metasurfaces have emerged as a fascinating framework for nonlinear optics, which have advantages of a compact footprint and unprecedented flexibility in manipulating light. But their nonlinear responses are generally limited by the short interaction lengths with light. Therefore, further enhancement is highly desired for building high-efficiency nonlinear devices.

Intelligent metasurfaces can recognize objects.

An on-chip optical neural network is built using metasurfaces, which can recognize objects with high accuracy.

Metasurfaces with high-Q resonances governed by topological edge state.

Achieving high-quality (Q)-factor resonances in metasurfaces is essential for various applications, including nano-lasers, nonlinear optics, and quantum optics. In this work, we propose a high-Q metasurface using a topological strategy: constructing the metasurface by stacking two conjugated nanopillar arrays with different topological invariants. Our study shows that a topological edge state steadily appears at the interfaces of the nanopillars, and a sharp transmission resonance with a Q-factor of more than 1000 can be obtained.

All-optical modulation of quantum states by nonlinear metasurface.

Metasurfaces have proven themselves an exotic ability to harness light at nano-scale, being important not only for classical but also for quantum optics. Dynamic manipulation of the quantum states is at the heart of quantum information processing; however, such function has been rarely realized with metasurfaces so far. Here, we report an all-optical dynamic modulation of the photonic quantum states using the nonlinear metasurface.

Strong in-plane scattering of acoustic graphene plasmons by surface atomic steps.

Acoustic graphene plasmons (AGPs) have ultrastrong field confinement and low loss, which have been applied for quantum effect exploration and ångström-thick material sensing. However, the exploration of in-plane scattering of AGPs is still lacking, although it is essential for the manipulation of ultraconfined optical fields down to atomic level. Here, by using scattering-type scanning near-field optical microscopy (s-SNOM), we show that the mid-infrared AGPs can be strongly scattered by atomic level height steps, even though the step height of the scatterer is four orders of magnitude smaller than the incident free wavelength.

Tunable terahertz topological edge and corner states in designer surface plasmon crystals.

In this work, we study topological edge and corner states in two-dimensional (2D) Su-Schrieffer-Heeger lattices from designer surface plasmon crystals (DSPCs), where the vertical confinement of the designer surface plasmons enables signal detection without the need of additional covers for the sample. In particular, the formation of higher-order topological insulator can be determined by the two-dimensional Zak phase, and the zero-dimensional subwavelength corner states are found in the designed DSPCs at the terahertz (THz) frequency band together with the edge states. Moreover, the corner state frequency can be tuned by modifying the defect strength, i.

Linewidth narrowing of aluminum breathing plasmon resonances in Bragg grating decorated nanodisks.

Plasmon resonances with high-quality are of great importance in light emission control and light-matter interactions. Nevertheless, inherent ohmic and radiative losses usually hinder the plasmon performance of metallic nanostructures, especially for aluminum (Al). Here we demonstrate a Bragg grating decorated nanodisk to narrow the linewidth of breathing plasmon resonances compared with a commensurate nanodisk.

Nanoinfrared Characterization of Bilayer Graphene Conductivity under Dual-Gate Tuning.

Dual-gate tuning on two-dimensional (2D) heterostructures can provide independent control of the carrier concentration and interlayer electrostatic potential, yielding novel electronic and optical properties. In this paper, by utilizing monolayer graphene as both the top gate and a plasmon wavelength magnifier, the optical properties of bilayer graphene (BLG) under dual-gate are quantitatively investigated by nanoinfrared imaging. The hybrid optical modes in the vertically coupled two-layer system are imaged from scattering-type scanning near-field microscopy (s-SNOM).

Machine learning powered ellipsometry.

Ellipsometry is a powerful method for determining both the optical constants and thickness of thin films. For decades, solutions to ill-posed inverse ellipsometric problems require substantial human-expert intervention and have become essentially human-in-the-loop trial-and-error processes that are not only tedious and time-consuming but also limit the applicability of ellipsometry. Here, we demonstrate a machine learning based approach for solving ellipsometric problems in an unambiguous and fully automatic manner while showing superior performance.

Phase-Transition Optical Activity in Chiral Metamaterials.

Optical activity from chiral metamaterials is both fundamental in electrodynamics and useful for polarization control applications. It is normally expected that due to infinitesimally small thickness, two-dimensional (2D) planar metamaterials cannot introduce large optical rotations. Here, we present a new mechanism to achieve strong optical rotation up to 90° by evoking phase transition in the 2D metamaterials through tuning coupling strength between meta-atoms.

Multifunctional and tunable trigate graphene metamaterial with "Lakes of Wada" topology.

Many plasmon-induced transparency (PIT) metamaterials previously reported had limited functions. Their tunabilities were realized by complex discrete structures, which greatly increased the difficulty and cost of device fabrication and adversely affected their resonance characteristics. It is an open question to adjust the Fermi levels of many graphene patterns with only a few in-plane electrodes.

Ultrastrong coupling of CdZnS/ZnS quantum dots to bonding breathing plasmons of aluminum metal-insulator-metal nanocavities in near-ultraviolet spectrum.

Strong coupling originating from excitons of quantum dots and plasmons in nanocavities can be realized at room temperature due to the large electromagnetic field enhancement of plasmons, offering building blocks for quantum information systems, ultralow-power switches and lasers. However, most of the current strong coupling effects were realized by the interaction between excitons and far-field light excited bright plasmon modes in the visible range. Beyond that, there is still a lack of direct imaging of polariton modes at the nanoscale.

Experimental observed plasmon near-field response in isolated suspended graphene resonators.

Because of extreme three-dimensional field confinement and easy electrically tunability, plasmons in graphene nanostructures are promising candidates for many applications, such as biosensing, photodetectors and modulators. However, up to now, graphene plasmons have been explored mostly on substrates. Scatterers, corrugations and dopants induced by substrates not only add damping to plasmons but also obscure the intrinsic electronic properties of graphene.

Tailorable Dynamics in Nonlinear Optical Metasurfaces.

Controlling light with light is essential for all-optical switching, data processing in optical communications and computing. Until now, all-optical control of light has relied almost exclusively on nonlinear optical interactions in materials. Achieving giant nonlinearities under low light intensity is essential for weak-light nonlinear optics.

Real-space mapping of mid-infrared near-field of Yagi-Uda antenna in the emission mode.

By using transmission-mode, scattering-type scanning near-field optical microscopy, we characterize the mid-infrared near-field properties of a Yagi-Uda antenna in the emission mode. The underlying near-field properties, including the near-field dipole-dipole coupling between antenna elements, are clearly observed. Moreover, even though most of the radiation energy is emitted into the substrate, by adopting two detector antennas, we managed to verify the unidirectionality and frequency-selectivity of the Yagi-Uda antenna in the air side.

Cathodoluminescence nanoscopy of open single-crystal aluminum plasmonic nanocavities.

Exact understanding of the plasmon response of aluminum (Al) nanostructures in deep subwavelengths is critical for the design of Al based plasmonic applications, such as the emission control of quantum dots and surface-enhanced resonance Raman scattering in the ultraviolet (UV) range. Here, the plasmonic properties of open triangle cavities patterned by a focused ion beam in single-crystal bulk Al were explored using cathodoluminescence. The resonant modes were determined by experimental spectra and deep subwavelength real-space mode patterns ranging from the visible to the UV, which agreed well with full-wave electromagnetic simulations.