排序方式: 共有32条查询结果,搜索用时 15 毫秒
1.
Mairesse Y Gobert O Breger P Merdji H Meynadier P Monchicourt P Perdrix M Salières P Carré B 《Physical review letters》2005,94(17):173903
We demonstrate the first experimental complete temporal characterization of high-harmonic XUV pulses by spectral phase interferometry, with an all-optical setup. This method allows us to perform single-shot measurements of the harmonic temporal profile and phase, revealing a remarkable shot-to-shot stability. We characterize harmonics generated in argon by a 50 fs 800 nm laser pulse. The 11th harmonic is found to be 22 fs long with a negative chirp rate of -4.8 x 10(27) s(-2). This duration can be reduced to 13 fs by modulating the polarization of the generating laser. The technique is easy to implement and could be routinely used in femtosecond XUV pump-probe experiments with harmonics. 相似文献
2.
Loch RA Dubrouil A Sobierajski R Descamps D Fabre B Lidon P van de Kruijs RW Boekhout F Gullikson E Gaudin J Louis E Bijkerk F Mével E Petit S Constant E Mairesse Y 《Optics letters》2011,36(17):3386-3388
We characterize the phase shift induced by reflection on a multilayer mirror in the extreme UV range (80-93?eV) using two techniques: one based on high order harmonic generation and attosecond metrology (reconstruction of attosecond beating by interference of two-photon transitions), and a second based on synchrotron radiation and measurements of standing waves (total electron yield). We find an excellent agreement between the results from the two measurements and a flat group delay shift (±40?as) over the main reflectivity peak of the mirror. 相似文献
3.
H. Wabnitz Y. Mairesse L. J. Frasinski M. Stankiewicz W. Boutu P. Breger P. Johnsson H. Merdji P. Monchicourt P. Salières K. Varjú M. Vitteau B. Carré 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(2):305-311
We investigate the carrier-envelope phase dependence of the total ionization yield for single and double ionization of xenon.
We compare our results to theoretical calculations and to the phase dependent asymmetry in photoelectron emission. We observe
that the phase dependence of the photoion yields, regardless if single or double ionization, is at least 2-3 orders of magnitude
below the photoelectron emission signal. We conclude that total photoionization yields are only very weakly dependent on the
carrier envelope phase, and that they are not a useful means for measurement of the phase. It seems possible that the broad
bandwidth of few-cycle pulses facilitates multiphoton ionization, which leads to a randomization of strong field ionization
phase dependencies. Besides, we observe that the spatial asymmetry in photoelectron emission appears to be useful as an indicator
for the laser pulse duration in the few cycle regime. 相似文献
4.
R. Von Der Mühll J. Ravez P. Hagenmuller P. Barbier M. Drache G. Mairesse 《Solid State Communications》1982,43(11):797-799
X-ray diffraction, calorimetric, dielectric and thermocurrent measurements have been carried out on Cs3BiCl6 ceramic samples. Three phase transitions have been detected at T1 = 395 K, T2 = 684 K and T3 = 727 K. The T3 transition is of ferroelastic-paraelastic type. The low temperature phase is characterized by remanent polarization. The depolarization current results probably from charge traps in potential minima which disappear at rising temperature. 相似文献
5.
Johnsson P López-Martens R Kazamias S Mauritsson J Valentin C Remetter T Varjú K Gaarde MB Mairesse Y Wabnitz H Salières P Balcou P Schafer KJ L'Huillier A 《Physical review letters》2005,95(1):013001
We use a train of sub-200 attosecond extreme ultraviolet (XUV) pulses with energies just above the ionization threshold in argon to create a train of temporally localized electron wave packets. We study the energy transfer from a strong infrared (IR) laser field to the ionized electrons as a function of the delay between the XUV and IR fields. When the wave packets are born at the zero crossings of the IR field, a significant amount of energy (approximately 20 eV) is transferred from the field to the electrons. This results in dramatically enhanced above-threshold ionization in conditions where the IR field alone does not induce any significant ionization. Because both the energy and duration of the wave packets can be varied independently of the IR laser, they are valuable tools for studying and controlling strong-field processes. 相似文献
6.
Queueing Systems - A Markovian single-server queue is studied in an interactive random environment. The arrival and service rates of the queue depend on the environment, while the transition... 相似文献
7.
Kovacev M Fomichev SV Priori E Mairesse Y Merdji H Monchicourt P Breger P Norin J Persson A L'Huillier A Wahlström CG Carré B Salières P 《Physical review letters》2005,95(22):223903
We demonstrate a new scheme for extreme ultraviolet (xuv) Fourier-transform spectroscopy based on the generation of two phase-locked high-harmonic beams. It allows us to measure for the first time interferograms at wavelengths as short as 90 nm, and open the perspective of performing high-resolution Fourier-transform absorption spectroscopy in the xuv. Our measurements also demonstrate that a precise control of the relative phase of harmonic pulses can be obtained with an accuracy on an attosecond time scale, of importance for future xuv pump-xuv probe attosecond spectroscopy. 相似文献
8.
We consider an infinite tandem queueing network consisting of ·/GI/1/∞ stations with i.i.d. service times. We investigate the asymptotic behavior of t(n, k), the inter-arrival times between customers n and n + 1 at station k, and that of w(n, k), the waiting time of customer n at station k. We establish a duality property by which w(n, k) and the “idle times”y(n, k) play symmetrical roles. This duality structure, interesting by itself, is also instrumental in proving some of the ergodic
results. We consider two versions of the model: the quadrant and the half-plane. In the quadrant version, the sequences of
boundary conditions {w(0,k), k∈ℕ} and {t(n, 0), n∈ℕ}, are given. In the half-plane version, the sequence {t(n, 0), n∈ℕ} is given. Under appropriate assumptions on the boundary conditions and on the services, we obtain ergodic results for
both versions of the model. For the quadrant version, we prove the existence of temporally ergodic evolutions and of spatially
ergodic ones. Furthermore, the process {t(n, k), n∈ℕ} converges weakly with k to a limiting distribution, which is invariant for the queueing operator. In the more difficult half plane problem, the aim
is to obtain evolutions which are both temporally and spatially ergodic. We prove that 1/n∑
k=1
n
w(0, k) converges almost surely and in L
1 to a finite constant. This constitutes a first step in trying to prove that {t(n,k), n∈ℤ} converges weakly with k to an invariant limiting distribution.
Received: 23 March 1999 / Revised version: 5 January 2000 / Published online: 12 October 2000 相似文献
9.
Let G be a free product of a finite family of finite groups,with the set of generators being formed by the union of thefinite groups. We consider a transient nearest-neighbour randomwalk on G. We give a new proof of the fact that the harmonicmeasure is a special Markovian measure entirely determined bya finite set of polynomial equations. We show that in severalsimple cases of interest, the polynomial equations can be explicitlysolved to get closed form formulae for the drift. The examplesconsidered are /2 /3, /3 /3, /k /k and the Hecke groups /2 /k.We also use these various examples to study Vershik's notionof extremal generators, which is based on the relation betweenthe drift, the entropy and the growth of the group. 相似文献
10.
Levesque J Mairesse Y Dudovich N Pépin H Kieffer JC Corkum PB Villeneuve DM 《Physical review letters》2007,99(24):243001
High harmonic emission in isotropic gases is polarized in the same direction as the incident laser polarization. Laser-induced molecular alignment allows us to break the symmetry of the gas medium. By using aligned molecules in high harmonic generation experiments, we show that the polarization of the extreme ultraviolet emission depends strongly on the molecular alignment and the orbital structure. Polarization measurements give insight into the molecular orbital symmetry. Furthermore, molecular alignment will allow us to produce attosecond pulses with time-dependent polarization. 相似文献