98%
921
2 minutes
20
Nonlinear second harmonic optical activity of graphene covering a gold photon sieve was determined for different polarizations. The photon sieve consists of a subwavelength gold nanohole array placed on glass. It combines the benefits of efficient light trapping and surface plasmon propagation to unravel different elements of graphene second-order susceptibility χ((2)). Those elements efficiently contribute to second harmonic generation. In fact, the graphene-coated photon sieve produces a second harmonic intensity at least two orders of magnitude higher compared with a bare, flat gold layer and an order of magnitude coming from the plasmonic effect of the photon sieve; the remaining enhancement arises from the graphene layer itself. The measured second harmonic generation yield, supplemented by semianalytical computations, provides an original method to constrain the graphene χ((2)) elements. The values obtained are |d31 + d33| ≤ 8.1 × 10(3) pm(2)/V and |d15| ≤ 1.4 × 10(6) pm(2)/V for a second harmonic signal at 780 nm. This original method can be applied to any kind of 2D materials covering such a plasmonic structure.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acs.nanolett.5b02494 | DOI Listing |
J Opt Soc Am A Opt Image Sci Vis
April 2025
The generation of vortex arrays holds significant potential for applications in multi-channel fiber optics communication and optical micromanipulation due to their unique properties. These applications necessitate vortex array generation devices that are structurally simple and cost-effective. In this study, a composite spiral photon sieve (CSPS) is proposed, leveraging the traditional spiral photon sieve as the foundational structure and integrating the hill-climbing algorithm (HCA) for design optimization.
View Article and Find Full Text PDFVet Parasitol
July 2025
Firat University, Faculty of Veterinary Medicine, Department of Parasitology, Elazig, Türkiye. Electronic address:
Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu lato, is a significant zoonotic disease with profound public health and economic impacts. This study evaluated egg detection methods, molecular diagnostics, and post-treatment shedding dynamics in experimentally infected dogs. Three three-month-old male dogs were included in the study.
View Article and Find Full Text PDFEur J Nucl Med Mol Imaging
August 2025
Department of Otolaryngology- Head and Neck Surgery, Stanford University, 900 Welch Road, 1st Floor, Stanford, CA, 94305, USA.
Purpose: Sentinel lymph node biopsy (SLNB) helps stage melanoma. Pre-surgical single-photon emission computed tomography/computed tomography (SPECT/CT) visualizes draining lymph nodes, but intraoperative gamma probe detection only estimates SLN location. This study evaluates augmented reality (AR) for projecting pre-surgical SLN imaging onto patients to aid precise localization and extraction.
View Article and Find Full Text PDFNanophotonics
November 2024
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
Structured beams carrying orbital angular momentum (OAM) provide powerful capabilities for applications in optical tweezers, super-resolution imaging, quantum optics, and ad-vanced microparticle manipulation. However, it is challenging for generate and control the OAM beams at the extreme ultraviolet (EUV) region due to the lack of suitable wave front shaping optics arise from being limited to the strong absorption of most materials. Here, we use a modified Fermat-spiral photon-sieve splitter to simultaneously generate two focused doughnut beams with opposite helical phase.
View Article and Find Full Text PDFMicrosc Microanal
November 2024
Department of Botany, University of Peshawar, Pakistan.
Micromorphological and phytochemical studies play a major role in quality control and standardization of traditional or herbal medications. In the present research, micromorphological assessment of Heliotropium rarifloum stocks was performed through light and scanning electron microscopies (LM & SEM). The anatomy of leaves, stem and root showed salient histological features.
View Article and Find Full Text PDF