نتایج جستجو برای: ultrashort

تعداد نتایج: 4043  

2009
Jian Jiao

Thermal analysis of a cylindrical tissue subject to a train of ultrashort pulse irradiations was made by developing a combined time-dependent radiation and conduction bio-heat transfer model. Ultrashort pulsed radiation transport in the cylindrical tissue is simulated using the transient discrete ordinate method. Treatment of focused beam is introduced. The model skin tissue is stratified as th...

Journal: :Physical review letters 2008
M A Lysaght P G Burke H W van der Hart

An attosecond pump-probe scheme that combines the use of a free-electron laser pulse with an ultrashort pulse is applied in order to explore the ultrafast excitation dynamics in Ne. We describe the multielectron dynamics using a new nonperturbative time-dependent R-matrix theory. This theory enables the interaction of ultrashort light fields with multielectron atoms and atomic ions to be determ...

1999
Sergio Ferrara Emery Sokatchev

We consider the harmonic superspaces associated to SU(2, 2/N) superconformal algebras. For arbitrary N , we show that massless representations, other than the chiral ones, correspond to [N2 ] “elementary” ultrashort analytic superfields whose first component is a scalar in the k antisymmetric irrep of SU(N) (k = 1 . . . [N2 ]) with top spin Jtop = ( N 2 − k 2 , 0 ) . For N = 2n we analyze UIR’s...

Journal: :Physical review. B, Condensed matter 1993
Ryan Deutscher Ferry

19 AS,-. 0 AZC Ohom on n ore 6 n~r,.s., -68 o-n Oh , by loc. aib The gating of edge states by ultrashort gates (50 nm) placed on normal quantum Hall effect devices is studied. In longer-gate devices, plateaus in the longitudinal resistance are found when an integer number of edge states is reflected from the gate. The expected quantized values of longitudinal resistance do not appear in the ult...

2014
Heather Thompson Joel Lammatao Matthew D. Hecht Aziz Yousif Benjamin R. Campbell Yoosuf N. Picard

Ultrashort pulsed lasers continue to see expanded application in many technologies such as microelectronics and precision manufacturing. The extremely short time duration (picosecond to femtosecond time scales) of these laser pulses create extremely non-equilibrium conditions during the heating and ablation of target materials. The result is generally efficient machining with little to no heat ...

1998
Daniel J. Kane

Frequency-resolved optical gating (FROG) is a technique to measure ultrashort laser pulses that optically constructs a spectrogram of a laser pulse. A two-dimensional (2-D) phase retrieval algorithm is used to extract the intensity and phase of a pulse from its spectrogram. We have improved a recently presented principal component generalized projections algorithm (PCGPA) making it easier to im...

2009
J. Wichmann F. Schwaneberg A. Lindinger

In our group, we perform successfully MALDI by using femtosecond laser techniques in order to examine the ionization process. One recent result is MALDI with ultrashort laser pulses in the near IR (central wavelength of =800 nm) [2]. In this wavelength regime, used matrix substances have no absorption bands. Experiments with different laser pulse durations suggest that multi photon ionization i...

2016
Yaakov Shaked Shai Yefet Avi Pe'er

Citation: Shaked Y, Yefet S, Pe’er A (2016) The Prism-Pair: Simple Dispersion Compensation and Spectral Shaping of Ultrashort Pulses. Int J Exp Spectroscopic Tech 1:007 Copyright: © 2016 Shaked Y, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the...

Journal: :Optics letters 2009
Derong Li Shaoqun Zeng Qingming Luo Pamela Bowlan Vikrant Chauhan Rick Trebino

The chirp acquired by a Gaussian ultrashort pulse due to angular dispersion, unlike that of plane waves, increases nonlinearly with propagation distance and eventually asymptotes to a constant. However, this interesting result has never been directly measured. In this Letter, we use two-dimensional spectral interferometry to measure the propagation dependence of the chirp for Gaussian ultrashor...

Journal: :Optics letters 2007
J Strohaber C Petersen C J G J Uiterwaal

We experimentally demonstrate that small misalignments of the pulse stretcher or compressor of our chirped-pulse-amplification laser can precompensate for angular chirp when producing ultrashort paraxial beam modes with holographic gratings. Using this approach we can eliminate one of the two gratings needed in our 2f-2f setup [Mariyenko, Opt. Express 13, 7599 (2005)]. This allows for up to an ...

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