Results 101 to 110 of about 409,972 (287)

Exciton Radiative Lifetimes in Hexagonal Diamond Ge and SixGe1–x Alloys

open access: yesAdvanced Optical Materials, EarlyView.
Strong room‐temperature photoluminescence reported in hexagonal Ge conflicts with theory predicting a nearly dark band edge. First‐principles calculations of excitonic radiative lifetimes fill a key gap in this debate, showing that pristine hexagonal Ge remains intrinsically weakly emissive, while Si alloying only modestly shortens the lifetime and ...
Michele Re Fiorentin   +2 more
wiley   +1 more source

Comparison of Optical Self-Phase Locked Loop Techniques for Frequency Stabilization of Oscillators

open access: yesIEEE Photonics Journal, 2014
Self-phase locked loop (SPLL) through long optical delay lines is investigated for improving the phase noise of the optoelectronic oscillator (OEO) and the voltage-controlled oscillator (VCO).
Li Zhang   +3 more
doaj   +1 more source

Spatial‐Wavelength Multiplexing Error‐Controlled Photonic Analog Computing System

open access: yesAdvanced Science, EarlyView.
A novel photonic integrated circuit prototype implementing the concept of general‐purpose analog computing and demonstrate its capability in radio frequency applications. The chip features a multichannel architecture and performs fully optical analog computation with frequency‐domain parallel processing. An FPGA‐based error‐correction algorithm aims to
Tao Zhu   +15 more
wiley   +1 more source

Revealing Dynamics, Communities, and Criticality from Data

open access: yesPhysical Review X, 2020
Complex systems such as ecological communities and neuron networks are essential parts of our everyday lives. These systems are composed of units which interact through intricate networks.
Deniz Eroglu   +3 more
doaj   +1 more source

An On‐Demand Neuromorphic Vision System Enabled by a Multi‐Paradigm Neuromorphic Device and Hierarchical Reconfigurability Designed from Device to System Level

open access: yesAdvanced Science, EarlyView.
An on‐demand ultra‐reconfigurable intelligent vision system with hierarchical reconfigurability from device to system levels is demonstrated. Through co‐design of a multi‐paradigm device, reconfigurable circuits, and adaptive system architecture/algorithms, the system enables seamless switching among spiking, non‐spiking, neuromorphic imaging (NI), and
Biyi Jiang   +7 more
wiley   +1 more source

Phase Diagrams and Piezoelectric Properties of Wurtzite Al1−x−yScxGdyN Heterostructural Alloys

open access: yesAdvanced Science, EarlyView.
This study demonstrates ferroelectricity and piezoelectric properties improvement of quaternary wurtzite Al1−x−yScxGdyN${\rm Al}_{1-x-y}{\rm Sc}_x{\rm Gd}_y{\rm N}$ films, guided by density functional theory calculations. Wurtzite Al1−x−yScxGdyN${\rm Al}_{1-x-y}{\rm Sc}_x{\rm Gd}_y{\rm N}$ films have a high optical bandgap, enhanced piezoelectric ...
Julia L. Martin   +11 more
wiley   +1 more source

Laser Chimeras as a paradigm for multi-stable patterns in complex systems

open access: yes, 2014
Chimera is a rich and fascinating class of self-organized solutions developed in high dimensional networks having non-local and symmetry breaking coupling features.
Larger, Laurent   +2 more
core   +1 more source

Energy‐Resolved Femtosecond Dynamics of Plasmon‐Induced Hole Injection at Au/GaN Heterointerfaces

open access: yesAdvanced Science, EarlyView.
We reveal the spectral signature of ultrafast nonthermal hot‐hole transfer at plasmonic heterointerfaces, which reshapes hot‐carrier relaxation dynamics and significantly enhances hydrogen evolution, providing a mechanistic basis for optimizing hot‐carrier utilization in photocatalysis.
Yuying Gao   +8 more
wiley   +1 more source

Donor–Acceptor Pentacene Analogues With Near‐Infrared Emission and Tunable Aromaticity

open access: yesAngewandte Chemie, EarlyView.
Air‐ and photostable heterocyclic pentacene analogues with donor and acceptor groups flanking a para‐quinodimethane core exhibit large dipole moments, narrow bandgaps, reversible redox behavior, and NIR‐I to NIR‐II absorption and emission with pronounced solvatochromism.
Krzysztof Nowak   +6 more
wiley   +2 more sources

Multilayer black phosphorus as broadband saturable absorber for pulsed lasers from 1 to 2.7 {\mu}m wavelength

open access: yes, 2015
It attracts wide interest to seek universe saturable absorber covering wavelengths from near infrared to mid-infrared band. Multilayer black phosphorus, with variable direct bandgap (0.3-2 eV) depending on the layer number, becomes a good alternative as ...
Guo, Zhinan   +6 more
core   +1 more source

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