Nanophotonics
November 2024
Ultrafast all-optical control has been a subject of wide-spread attention as a method of manipulating optical fields using light excitation on extremely short time scales. As a fundamental form of ultrafast all-optical control, all-optical switching has achieved sub-picosecond switch speeds in the visible, infrared, and terahertz spectral regions. However, due to the lack of suitable materials, ultrafast all-optical control in the ultraviolet range remains in its early stages.
View Article and Find Full Text PDFHot spots can generate intense local electromagnetic (EM) fields, thereby boosting diverse innovative applications. However, these applications may face challenges due to their subtle structural changes that can significantly impact their EM field strength. Herein, we report a large-scale synthesis of monodisperse, highly spherical, single crystalline (SC) Au nanospheres (Au NSs) with tunable sizes ranging from 38 to 92 nm for constructing uniform and reproducible hot spots with a nanosphere-on-mirror (NSoM) configuration.
View Article and Find Full Text PDFJ Chem Theory Comput
December 2024
The propulsion mechanisms and collective dynamics of chemically powered Janus sphere dimers at the micro- and nanoscales, confined in a quasi-two-dimensional geometry, are investigated using a coarse-grained microscopic dynamical model. These active Janus dimers consist of two identical Janus spheres, featuring a catalytic cap on one hemisphere. The chemical reaction taking place on the catalytic surface generates asymmetric concentration gradients of product molecules around the Janus sphere, leading to the self-propulsion of the dimers.
View Article and Find Full Text PDFObjective: Identifying patients at high risk for cardiac arrest-associated acute kidney injury (CA-AKI) helps in early preventive interventions. This study aimed to establish and validate a high-risk nomogram for CA-AKI.
Methods: In this retrospective dataset, 339 patients after cardiac arrest (CA) were enrolled and randomized into a training or testing dataset.
Ag nanoparticles sputtered on silicon wafer are used as masks for the fabrication of silicon columns by ion etching, which induces the growth of the inclined Ag nanorod by inclined Ag sputtering. V-shaped and Z-shaped Ag nanorods can be obtained by varying incline angles and deposition times. SERS detection and FDTD simulation are used to compare and investigate the enhanced electromagnetic coupling of incline nanorod arrays with different shapes in three-dimensional space, which indicates that Z-shaped nanorods show good SERS properties.
View Article and Find Full Text PDFMicromachines (Basel)
September 2023
Organized two-dimensional polystyrene bead arrays perform ion etching, and protruding nanostructures are created on polystyrene beads due to the shadow effects from the ring beads, leading to nucleus selection and growth in Au nanostructure deposition. Ag nanostructures are prepared via plasmon-mediated chemical reactions (PMCRs), leading to the Ag nanocavity geometry of the honeycomb pattern when the etching time and Ag growth time are tuned. Due to the strong electromagnetic coupling, the Ag honeycomb-shaped nanocavity array works as the SERS substrate with high sensitivity and good repeatability, which is used to detect thiram pesticide residues with a concentration down to 10 M.
View Article and Find Full Text PDFThe gigahertz acoustic vibration of nano-optomechanical systems plays an indispensable role in all-optical manipulation of light, quantum control of mechanical modes, on-chip data processing, and optomechanical sensing. However, the high optical, thermal, and mechanical energy losses severely limit the development of nano-optomechanical metasurfaces. Here, we demonstrated a high-quality 5 GHz optoacoustic vibration and ultrafast optomechanical all-optical manipulation in a sub-5 nm tip-supported nano-optomechanical metasurface (TSNOMS).
View Article and Find Full Text PDFSerum lactate dehydrogenase (LDH) has been identified as an independent risk factor for predicting all-cause mortality in patients with multiple diseases. However, the prognostic value of LDH levels in post-cardiac arrest patients remains uncertain. This study aimed to assess the association between LDH and mortality in intensive care unit (ICU) patients after cardiac arrest.
View Article and Find Full Text PDFIt is very important to build uniform large-area dense hotspots to improve the surface-enhanced Raman scattering (SERS) detection limit. In our research, we designed and prepared a new flexibile SERS substrate with ultradense hot spots that has the advantages of high sensitivity, good repeatability, easy fabrication, and low cost. Due to the special dense hot spot structure, the substrate reaches a SERS enhancement factor of 2.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2022
Based on etched PS sphere arrays, the different growths of Ag nanoparticles with tunable LSPR are designed when SiO-25 nm/Ag-30 nm/SiO-100 nm sandwich nanocavity structures are annealed at 500 °C, including the hexagonal silver nanoparticle rings, circular silver nanoparticle rings, and aggregated silver nanoparticles. The uniformity of particle size and regularity of position generate enhanced electromagnetic field and good surface-enhanced Raman spectroscopy signals as confirmed by UV-vis observation and finite difference time domain method simulation. The developed nanostructures are effectively used as stable, nonreproducible, and markable anti-counterfeiting signs.
View Article and Find Full Text PDFMetal-dielectric heterostructures have shown great application potentials in physics, chemistry and material science. In this work, we have designed and manufactured ordered metal-dielectric multiple heterostructures with tunable optical properties, which can be as large as the order of square centimeters in size. We experimentally realized that the surface-enhanced Raman scattering signal of the periodic multiple heterostructures increased 50 times compared with the silicon nanodisk-gold film arrays, which is attributed to the large-scale hotspots and high efficient coupling between the optical cavities and surface plasmon resonance modes.
View Article and Find Full Text PDFPlasmonic nanocavities offer prospects for the amplification of inherently weak nonlinear responses at subwavelength scales. However, constructing these nanocavities with tunable modal volumes and reduced optical losses remains an open challenge in the development of nonlinear nanophotonics. Herein, we design and fabricate three-dimensional (3D) metal-dielectric-metal (MDM) plasmonic nanocavities that are capable of amplifying second-harmonic lights by up to three orders of magnitude with respect to dielectric-metal counterparts.
View Article and Find Full Text PDFPlasmonic sensors exhibit tremendous potential to accomplish real-time, label-free, and high-sensitivity biosensing. Gold nanohole array (GNA) is one of the classic plasmonic nanostructures that can be readily fabricated and integrated into microfluidic platforms for a variety of applications. Even though GNA has been widely studied, new phenomena and applications are still emerging continuously expanding its capabilities.
View Article and Find Full Text PDFBoosting nonlinear frequency conversions with plasmonic nanostructures at near-ultraviolet (UV) frequencies remains a great challenge in nano-optics. Here we experimentally design and fabricate a plasmon-enhanced second-harmonic generation (PESHG) platform suitable for near-UV frequencies by integrating aluminum materials with grating configurations involved in structural heterogeneity. The SHG emission on the proposed platform can be amplified by up to three orders of magnitude with respect to unpatterned systems.
View Article and Find Full Text PDFChanging the morphology of noble metal nanoparticles and polarization dependence of nanoparticles with different morphologies is an important part of further research on surface plasma enhancement. Therefore, we used the method based on Matlab simulation to provide a simple and effective method for preparing the morphologies of Au nanoparticles with different morphologies, and prepared the structure of Au nanoparticles with good uniformity and different morphologies by oblique angle deposition (OAD) technology. The change of the surface morphology of nanoparticles from spherical to square to diamond can be effectively controlled by changing the deposition angle.
View Article and Find Full Text PDFNanomaterials (Basel)
October 2019
Controlling chemical reactions by plasma is expected to be a new method for improving the structural properties of substrates. An Au nanojar array was prepared when Au was deposited onto a 2D polystyrene (PS) array. The site-selective chemical growth of Ag nanoparticle rings was realized around the Au nanojar necks by a local surface plasmon resonance (LSPR)-assisted chemical reaction.
View Article and Find Full Text PDFHere, we develop a new method to improve the surface-enhanced Raman spectroscopy (SERS) activity of ZnO using Mg doping combined with noble metals. Highly aligned silver nanoparticles (AgNPs) decorated on an array of Mg-doped ZnO (MZO@Ag) were fabricated. Using rhodamine 6G as the probe molecule, SERS indicated that the MZO@Ag substrate possesses perfect sensitivity, homogeneity, and chemical stability.
View Article and Find Full Text PDFThe present study aimed to discover potential biomarkers for predicting the prognosis of acute respiratory distress syndrome (ARDS) in conjunction with lung ultrasound (LUS). Blood samples from 112 ARDS patients were collected to compare their partial oxygen pressure (PaO)/fraction of inspired oxygen (FiO), positive end-expiratory pressure (PEEP), lactic acid, sequential organ failure assessment (SOFA) score, clinical pulmonary infection score (CPIS) and APACHE II score. Kaplan-Meier plots and the log-rank test were performed to analyse the association between the platelet-activating factor acetylhydrolase (PAFAH) G994T polymorphism and the outcome of ARDS regarding mortality.
View Article and Find Full Text PDFHexagonal Ag nanoparticle arrays are exclusively grown on top of the interstices of Au nanobowl arrays. The photoinduced effect of the enhanced electromagnetic field between Au nanobowls accelerated the chemical reaction and is responsible for Ag growth in defined local positions. The enhanced electric field of the Au nanobowl array induced a photoreaction, which resulted in Ag growth in the hot area.
View Article and Find Full Text PDFWe discuss how the controllable carrier influences the localized surface plasmon resonance (LSPR) and charge transfer (CT) in the same system based on ultraviolet-visible and surface-enhanced Raman scattering (SERS) measurements. The LSPR can be easily tuned from 580 to 743 nm by changing the sputtering power of CuS in the Ag and CuS composite substrate. During this process, surprisingly, we find that the LSPR is proportional to the sputtering power of CuS.
View Article and Find Full Text PDFAg⁻SiO₂ nanomace arrays were prepared on a two-dimensional ordered colloidal (2D) polystyrene sphere template by co-sputtering Ag and SiO₂ in a magnetron sputtering system. The lateral size of the nanomaces and the distance between the neighbor nanomaces were controlled by adjusting the etching time of the 2D template. The nanomaces were composed of SiO₂-isolated Ag nanoparticles, which produced surface-enhanced Raman scattering (SERS) enhancement, and 3D hot spots were created between the neighbor nanomaces.
View Article and Find Full Text PDFNanomaterials (Basel)
June 2018
Emerging opportunities based on two-dimensional (2D) layered structures can utilize a variety of complex geometric architectures. Herein, we report the synthesis and properties of a 2D+0D unique ternary platform-core-shell nanostructure, termed Ag@Cu₂O-rGO, where the reduced graphene oxide (rGO) 2D acting as a platform is uniformly decorated by Ag@Cu₂O core-shell nanoparticles. Cu₂O nanoparticles occupy the defect positions on the surface of the rGO platform and restore the conjugation of the rGO structure, which contributes to the significant decrease of the / intensity ratio.
View Article and Find Full Text PDFHexagonal close-packed tilted Ag nanorod arrays that exhibit excellent uniformity and reproducibility were prepared. The tilt angle was easily controlled by regulating the sputtering angle, accompanied by a reduction and constancy in the gap size of adjacent nanorods, which is 30° and 90° relative to the sputtering direction. The surface enhanced Raman spectroscopy (SERS) technique was used to characterize the interaction of tilted Ag nanorod arrays with polarized laser excitation.
View Article and Find Full Text PDFIntroduction: Aconitine is a highly toxic diterpenoid alkaloid, produced by plants of the Aconitum genus, that is still used in Chinese herbal medicines. Aconitine poisoning remains common in China and other parts of Asia.
Case Report: A 48-year-old man received a diagnosis of aconitine poisoning after ingesting herbal medicinal wine made with caowu, which is made from Aconitum kusnezoffii roots, and was admitted to our hospital' s emergency department.