An analytic model is developed to study the dynamic response of carrier-depletion silicon ring modulators. Its validity is confirmed by a detailed comparison between the modeled and the measured small signal frequency response of a practical device. The model is used to investigate how to maximize the optical modulation amplitude (OMA) and how the OMA could be traded for the bandwidth by tuning the coupling strength and the operation wavelength. Our calculation shows that for a ring modulator with equal RC time constant and photon lifetime, if its operation wavelength shifts from the position of the maximum OMA towards the direction that is away from the resonance, the 3dB modulation bandwidth increases ~2.1 times with a penalty of 3 dB to the OMA.
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http://dx.doi.org/10.1364/OE.22.015178 | DOI Listing |
Environ Sci Technol
January 2025
State Key Laboratory of Heavy Oil Processing, Key Laboratory of Optical Detection Technology for Oil and Gas, College of Science, China University of Petroleum, Beijing 102249, PR China.
The purification efficiency of autoexhaust carbon strongly depends on the heterogeneous interface structure between active metal and oxide, which can modulate the local electronic structure of defect sites to promote the activation of reactant molecules. Herein, the high-dispersion CuO clusters supported on the well-defined CeO nanorods were prepared using the complex deposition slow method. The formation of heteroatomic Cu-O-Ce interfacial structural units as active sites can capture electrons to achieve activation of the NO and O molecules.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
PASTEUR, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 24, rue Lhomond, Paris, 75005, France.
Imaging luminescence kinetics is invaluable in many fields, including biology and chemistry. However, the luminescence lifetime of most photo-activated states is in the low ns-µs range and its measurement requires adding costly image intensifiers to cameras to access the fast phenomena present. Here, the Rectified Imaging under Optical Modulation (RIOM) and Heterodyne Imaging under Optical Modulation (HIOM) protocols make this possible with standard low-cost cameras only, even under ambient light.
View Article and Find Full Text PDFNat Nanotechnol
January 2025
Bay Area Center for Electron Microscopy, Songshan Lake Materials Laboratory, Dongguan, China.
Skyrmions can form regular arrangements, so-called skyrmion crystals (SkXs). A mode with multiple wavevectors q then describes the arrangement. While magnetic SkXs, which can emerge in the presence of Dzyaloshinskii-Moriya interaction, are well established, polar skyrmion lattices are still elusive.
View Article and Find Full Text PDFNat Commun
January 2025
School of Nano-Technology and Nano-Bionics, University of Science and Technology of China, Hefei, China.
Electrochromic materials were discovered in the 1960s when scientists observed reversible changes between the light and dark states in WO thin films under different voltages. Since then, researchers have identified various electrochromic material systems, including transition metal oxides, polymer materials, and small molecules. However, the electrochromic phenomenon has rarely been observed in non-metallic elemental substances.
View Article and Find Full Text PDFNeural Regen Res
January 2025
Molecular Neuropharmacology Laboratory and Eye-Brain Research Center, State Key Laboratory of Ophthalmology, Optometry and Vision Science, School of Ophthalmology & Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
The excessive buildup of neurotoxic α-synuclein plays a pivotal role in the pathogenesis of Parkinson's disease, highlighting the urgent need for innovative therapeutic strategies to promote α-synuclein clearance, particularly given the current lack of disease-modifying treatments. The glymphatic system, a recently identified perivascular fluid transport network, is crucial for clearing neurotoxic proteins. This review aims to synthesize current knowledge on the role of the glymphatic system in α-synuclein clearance and its implications for the pathology of Parkinson's disease while emphasizing potential therapeutic strategies and areas for future research.
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