We investigate efficient fourth-harmonic generation in a single two-dimensional (2D) quadratically nonlinear photonic crystal. We propose a novel parametric process that starts with phase-matched generation of a pair of symmetric second-harmonic waves, which then interact to produce a fourth-harmonic wave that is collinear to the fundamental. We show that this process is more efficient than conventional fourth-harmonic-generation schemes by a factor that reaches 4 at low intensities and discuss how to design and optimize the nonlinear 2D photonic crystals that are implemented in LiNbO(3) and LiTaO(3) .
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http://dx.doi.org/10.1364/ol.26.000539 | DOI Listing |
Nano Lett
January 2025
The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, School of Physics and Teda Applied Physics Institute, Renewable Energy Conversion and Storage Center, State Key Laboratory of Photovoltaic Materials and Cells, Nankai University, Tianjin 300071, China.
Ion transport through atomically thin nano/subnanopores, such as those in monolayer graphene, presents challenges to traditional ion conduction models, primarily due to extreme confinement effects and hydration interactions. Under these conditions, existing models fail to account for conductance behaviors at the nano- and subnanometer scales. In this study, we perform a combined experimental and theoretical investigation of ion transport in monolayer graphene nano/subnanopores across varying salt concentrations.
View Article and Find Full Text PDFACS Nano
January 2025
Conte Center for Polymer Research, Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States.
Bottlebrush block copolymers (BBCPs) are a unique class of materials that contain a backbone with densely grafted and chemically distinct polymeric side chains. The nonlinear architecture of BBCPs provides numerous degrees of freedom in their preparation, including control over key parameters such as grafting density, side chain length, block arrangement, and overall molecular weight. This uniquely branched structure provides BBCPs with several important distinctions from their linear counterparts, including sterically induced side chain and backbone conformations, rapid and large self-assembled nanostructures, and reduced or eliminated entanglement effects (assuming sufficient grafting density and that the molecular weight of the side chains is below their respective entanglement molecular weight).
View Article and Find Full Text PDFSci Rep
January 2025
Key Laboratory of Micro/nano Devices and Systems, Ministry of Education, North University of China, Taiyuan, 030051, China.
As the hyperentanglement of photon systems holds lots of remarkable applications for enhancing channel capacity with less quantum resource, the interconversion of various hyperentangled states warrants in-depth investigation and becomes a vital work for quantum information technologies. Here we realize completely mutual conversions between spatial-polarization hyperentangled Knill-Laflamme-Milburn state and hyperentangled W state for three-photon systems, resorting to hyperparallel quantum control gates and the practical nonlinear interaction of nitrogen-vacancy centers coupled with whispering-gallery-mode microresonators. The hyperparallel quantum gates, i.
View Article and Find Full Text PDFNanoscale
January 2025
School of Chemistry and Chemical Engineering, Center of Free Electron Laser & High Magnetic Field, Key Laboratory of Structure and Functional Regulation of Hybrid Materials Ministry of Education, Key Laboratory of Functional Inorganic Materials Chemistry of Anhui Province, and Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials of Anhui Province, Anhui University, P.R. China.
Currently, the study of cuproptosis focuses on the Cu-induced morphology changes in mitochondria (Mito), and the observation of the effect of endoplasmic reticulum (ER)-related Cu content on cuproptosis is relatively lacking. Herein, we have developed a hydroxyflavone (HF)-based NIR excited two-photon fluorescent probe, BHCO, that exhibits specific recognition of Cu with high resolution. BHCO-Cu (Cu2BC) can lead to DLAT protein aggregation, triggering cuproptosis.
View Article and Find Full Text PDFACS Photonics
January 2025
Department of Physics, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, Pennsylvania 15218, United States.
We report the canonical properties of the Bose-Einstein condensation of polaritons in the weak coupling regime, seen previously in many low-temperature experiments, at room temperature in a GaAs/AlGaAs structure. These effects include a nonlinear energy shift of the polaritons, showing that they are not noninteracting photons, and dramatic line narrowing due to coherence, giving coherent emission with a spectral width of 0.24 meV at room temperature with no external stabilization.
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