نتایج جستجو برای: ultrafast phenomenon

تعداد نتایج: 170044  

Journal: :Nature communications 2013
A J McCulloch D V Sheludko M Junker R E Scholten

Ultrafast electron diffraction enables the study of molecular structural dynamics with atomic resolution at subpicosecond timescales, with applications in solid-state physics and rational drug design. Progress with ultrafast electron diffraction has been constrained by the limited transverse coherence of high-current electron sources. Photoionization of laser-cooled atoms can produce electrons ...

Journal: :The Review of scientific instruments 2015
S P Weathersby G Brown M Centurion T F Chase R Coffee J Corbett J P Eichner J C Frisch A R Fry M Gühr N Hartmann C Hast R Hettel R K Jobe E N Jongewaard J R Lewandowski R K Li A M Lindenberg I Makasyuk J E May D McCormick M N Nguyen A H Reid X Shen K Sokolowski-Tinten T Vecchione S L Vetter J Wu J Yang H A Dürr X J Wang

Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast...

2012
Jianfa Zhang Kevin F MacDonald Nikolay I Zheludev

According to the fundamental Huygens superposition principle, light beams traveling in a linear medium will pass though one another without mutual disturbance. Indeed, the field of photonics is based on the premise that controlling light signals with light requires intense laser fields to facilitate beam interactions in nonlinear media, where the superposition principle can be broken. Here we c...

1998
Mayukh Bhattacharya Pinaki Mazumder

Threshold gates consisting of resonant tunneling diodes (RTDs) in conjunction with HBTs or CHFETs or MOSFETs can form extremely compact, ultrafast, digital logic alternatives, and may be used for digital signal processing applications in the near future. The resonant tunneling phenomenon causes these circuits to exhibit super-high-speed switching capabilities. Additionally, by virtue of being t...

2015
JOHN WALLACE

While ultrafast (picosecond and femtosecond) lasers are an essential subset of the lasers used today in industry and the medical arena (for example, machining glass for smartphone screens for the former, and laser eye surgery for the latter), it is the use of ultrafast lasers in research that allows such lasers to show their true colors, sometimes literally. Indeed, science is where it all bega...

2004
Linlin Qiu Stephen J. Hagen

Protein folding is a diffusional process, and the speed of folding is controlled by the frictional forces that act on the polypeptide chain. Several previous studies have suggested that the bulk viscosity of the solvent is the only important source of friction in folding reactions. By contrast, our studies of the folding dynamics of the Tryptophan Cage, a small, ultrafast-folding protein, show ...

2013
Arunabha Ghosh Viet Thong Le Jung Jun Bae Young Hee Lee

Electrochemical capacitors with fast charging-discharging rates are very promising for hybrid electric vehicle industries including portable electronics. Complicated pore structures have been implemented in active materials to increase energy storage capacity, which often leads to degrade dynamic response of ions. In order to understand this trade-off phenomenon, we report a theoretical model b...

2017
Joel D. Cox Andrea Marini F. Javier García de Abajo

High-harmonic generation in condensed-matter systems is both a source of fundamental insight into quantum electron motion and a promising candidate to realize compact ultraviolet and ultrafast light sources. While graphene is anticipated to efficiently generate high-order harmonics due to its anharmonic charge-carrier dispersion, experiments performed on extended samples using THz illumination ...

Journal: :Journal of the Optical Society of America. A, Optics, image science, and vision 2001
D M Marom D Panasenko P C Sun Y Fainman

The operational characteristics of a time-to-space processor based on three-wave mixing for instantaneous imaging of ultrafast waveforms are investigated. We assess the effects of various system parameters on the processor's important attributes: time window of operation and signal conversion efficiency. Both linear and nonlinear operation regimes are considered, with use of a Gaussian pulse pr...

Journal: :Optics express 2007
Fang Shan Joshua D Carter Ting Guo

Using magnetic fields to differentiate the effects of electrons and x-rays, it was discovered that single strand breaks in supercoiled DNA were mainly caused by the energetic ultrafast electrons rather than the ultrafast x-ray photons emitted from the same table-top ultrafast x-ray source. At constant pulse energy of the driving laser pulses, shorter laser pulses produced more strand breaks tha...

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