نتایج جستجو برای: ultrafast phenomenon

تعداد نتایج: 170044  

Journal: :Optics express 2010
Guichuan Xing Hongchen Guo Xinhai Zhang Tze Chien Sum Cheng Hon Alfred Huan

The ultrafast saturable absorption in graphene is experimentally and theoretically investigated in the femtosecond (fs) time regime. This phenomenon is well-modeled with valence band depletion, conduction band filling and ultrafast intraband carrier thermalization. The latter is dominated by intraband carrier-carrier scattering with a scattering time of 8 ( +/- 3) fs, which is far beyond the ti...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2014
Roni Vardi Hagar Marmari Ido Kanter

We experimentally show that the neuron functions as a precise time integrator, where the accumulated changes in neuronal response latencies, under complex and random stimulation patterns, are solely a function of a global quantity, the average time lag between stimulations. In contrast, momentary leaps in the neuronal response latency follow trends of consecutive stimulations, indicating ultraf...

Journal: :Physical chemistry chemical physics : PCCP 2015
Kuiwen Zhao Huiying Wu

Determining water structure in nanopores and its influence on water transport behaviour is of great importance for understanding and regulating the transport across nanopores. Here we report an ultrafast-slow flow transition phenomenon for water transport across nanopores of carbon nanotubes owing to the change in water structure in nanopores induced by temperature. By performing extensive mole...

2014
Yu Zou Jun Cai Xiulan Huai Fang Xin Zhixiong Guo

a r t i c l e i n f o Molecular dynamics simulations are carried out to study the thermal and mechanical phenomena of heat conduction induced by ultrafast laser heating of nanoscale Si films. A distribution of internal heat source obeying Beer–Lambda law is applied to model the laser energy deposition in the film and to calculate the induced temperature and stress distributions. Thermal waves a...

Journal: :The Journal of chemical physics 2013
M N Piancastelli R Guillemin M Simon H Iwayama E Shigemasa

Following core excitation in an isolated molecule, ultrafast dissociation of one particular chemical bond can occur, where "ultrafast" is defined as taking place during the lifetime of the core hole, of the order of few femtoseconds. The signature of such phenomenon can be observed in resonant Auger spectra following core excitation. We present here an investigation of ultrafast dissociation fo...

2009
P. DOMBI P. RÁCZ B. BÓDI

Surface plasmon enhanced electron acceleration is a recently discovered efficient particle acceleration phenomenon in the nanoscale-confined field of surface electromagnetic waves. For the generation and spatial/spectral control of keV-energy electrons generated, this way few-cycle laser pulses can be utilized particularly well. We present numerical results based on a simple model of this pheno...

Journal: :The Review of scientific instruments 2016
J Diaz-Fortuny M Maestro J Martin-Martinez A Crespo-Yepes R Rodriguez M Nafria X Aymerich

A new system for the ultrafast characterization of resistive switching phenomenon is developed to acquire the current during the Set and Reset process in a microsecond time scale. A new electronic circuit has been developed as a part of the main setup system, which is capable of (i) applying a hardware current limit ranging from nanoampers up to miliampers and (ii) converting the Set and Reset ...

2015
A. Y. Elezzabi P. Maraghechi S. R. Greig

We report the observation of terahertz (THz) electric field induced conductivity modulation in sub-wavelength gold plasmonic media. Through all-THz pump-probe time-resolved transmission spectroscopy, we demonstrate that the presence of induced surface charges influences near-field mediated light propagation. The phenomenon is ascribed to the enhanced metal conductivity due to enhanced surface d...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان فارس - دانشکده علوم 1388

کلیدزنی نوری یک ضرورت برای سیستم های مدرن ارتباطی و پایه اصلی ساخت عناصر منطقی و پردازشگرهای تمام نوری محسوب می شود. مزدوج موازی غیرخطی به عنوان کلید تمام نوری و عنصر منطقی، پتانسیل زیادی برای طراحی محاسبگرهای اپتیکی و سیستم های ارتباطی فوق سریع دارد. خودسرازیری نتیجه ای از شدت وابسته به سرعت گروه است و منجر به ناتقارنی در پهن شدگی طیف توسط خودفازی در پالس های با پهنای کم می شود. پراکندگی راما...

Journal: :Optics express 2015
Wen-Xing Yang Ai-Xi Chen Ziwen Huang Ray-Kuang Lee

We study ultrafast excitonic population inversion resulting from the interaction of a semiconductor quantum dot (SQD) with localized surface plasmons. The plasmonic enhanced fields are generated when a metallic nanoparticle (MNP) is subject to a nonlinear chirped few-cycle pulse train. By numerically solving the time-dependent Bloch equations beyond the rotating-wave approximation, we show that...

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