Two-dimensional (2D) layered materials without centrosymmetry, such as GaSe, have emerged as promising novel optical materials due to large second-order nonlinear susceptibilities. However, their nonlinear responses are severely limited by the short interaction between the 2D materials and light, which should be improved by coupling them with photonic structures with strong field confinement. Here, we theoretically design photonic crystal circular Bragg gratings (CBG) based on hole gratings with a quality factor as high as = 8 × 10, a mode volume as small as = 1.18 (/), and vertical emission of light field in silicon nitride thin film platform. Experimentally, we achieved a value up to nearly 4 × 10, resulting in a 1,200-fold enhancement of second harmonic generation from GaSe flakes with a thickness of 50 nm coupling to the CBG structures under continuous-wave excitation. Our work endows silicon-based photonic platforms with significant second-order nonlinear effect, which is potentially applied in on-chip quantum light sources and nonlinear frequency conversion.
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http://dx.doi.org/10.1515/nanoph-2024-0282 | DOI Listing |
Clin Neurophysiol
December 2024
Université de Lorraine, CNRS, IMoPA, 29 Avenue du Maréchal de Lattre de Tassigny, F-54000 Nancy, France; Université de Lorraine, CHRU-Nancy, Service de Neurologie, 29 Avenue du Maréchal de Lattre de Tassigny, F-54000 Nancy, France. Electronic address:
Objective: Combining electroencephalographic (EEG) recording and fast periodic visual stimulation (FPVS) to provide an implicit, objective and sensitive electrophysiological measure of semantic word categorization impairment in Alzheimer's Disease (AD).
Methods: Twenty-five AD patients and 25 matched elderly healthy controls were tested with a validated FPVS-EEG paradigm in which different written words of the same semantic category (cities) appear at a fixed frequency of 4 words per second (4 Hz) for 70 seconds. Words from a different semantic category (animal) appear every 4 stimuli (i.
Dalton Trans
December 2024
Research Center for Crystal Materials, State Key Laboratory of Functional Materials and Devices for Special Environmental Conditions; Xinjiang Key Laboratory of Functional Crystal Materials; Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China.
In recent years, hydroxyborates with excellent properties have attracted much attention. Through dedicated efforts, three new hydroxyborates-KBO(OH), CsBO(OH), and CsBO(OH)-have been successfully synthesized in a closed system. The ultraviolet (UV) cut-off edges of both KBO(OH) and CsBO(OH) are below 200 nm, indicating their potential as candidates for deep-ultraviolet (DUV) materials.
View Article and Find Full Text PDFLasers Surg Med
December 2024
James C Wyant College of Optical Sciences, University of Arizona, Tucson, Arizona, USA.
Objectives: To study the healing response of rat Achilles tendon when lacerated or treated with intense therapeutic ultrasound (ITU) via utilization of multiphoton microscopy (MPM) imaging and histology.
Materials And Methods: The right Achilles tendon of each Sprague Dawley rat within a cohort was partially lacerated. 1 to 2 days post-surgery, each rat received ITU treatment of the Achilles tendon on either the right or left leg.
J Am Chem Soc
December 2024
Department of Chemistry, National University of Singapore, Singapore 117543, Singapore.
Electrically switchable second harmonic generation (SHG) is highly valuable in electro-optic modulators, which can be deployed in data communication and quantum optics. Coupling circular dichroism (CD) with an electrically controlled SHG process is advantageous because it enhances the signal transmission bandwidth and security while enabling multiple modulation modes for optical logic. However, ferroelectrically switchable chiral second-order nonlinearity is rarely reported.
View Article and Find Full Text PDFCardiooncology
December 2024
Department of Pathology and Laboratory Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.
Background: Cancer patients are known to be associated with increased risk of cardiovascular disease. However, no studies have examined the differential impact of hematologic malignancies (HMs) and solid tumors (STs) on cardiac morphology at the tissue level.
Objective: We aimed to examine histopathological features alongside cardiovascular biomarkers in patients with HMs and STs who underwent post-mortem evaluation.
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