Search results for "Ultra"
showing 10 items of 4451 documents
ULTRA-FAST FLASH OBSERVATORY (UFFO) FOR OBSERVATION OF EARLY PHOTONS FROM GAMMA RAY BURSTS
2013
I.H. Park, S. Ahmad, P. Barrillon, S. Brandt, C. Budtz-Jorgensen, A.J. Castro-Tirado, P. Chen, Y.J. Choi, P. Connell, S. Dagoret-Campagne, C. Eyles, B. Grossan, M.–H.A. Huang, A. Jung, S. Jeong, J.E. Kim, M.B. Kim, S.-W. Kim, Y.W. Kim, A.S. Krasnov, J. Lee, H. Lim, E.V. Linder, T.–C. Liu, N. Lund, K.W. Min, G.W. Na, J.W. Nam, M.I. Panasyuk, J. Ripa, V. Reglero, J.M. Rodrigo, G.F. Smoot, J.E. Suh, S. Svertilov, N. Vedenkin, M.–Z. Wang, I. Yashin Ewha Womans University, Seoul, Korea University of Paris-Sud 11, Orsay, France Technical University of Denmark, Copenhagen, Denmark Instituto de Astrofisica de Andalucia CSIC, Granada, Spain National Taiwan University, Taipei, Taiwan Korea Advanced I…
Gain Dynamics after Ultrashort Pulse Trains in Quantum Dot based Semiconductor Optical Amplifiers
2007
We study the gain dynamics in QD-based SOAs after excitation with fs-pulse trains of up to THz repetition rates. A complete ground-state gain recovery is found for 200 GHz repetition rates and injection currents around 90 mA.
Complete characterization of terahertz pulse trains generated from nonlinear processes in optical fibers
2001
The measurement technique of frequency-resolved optical gating (FROG) is used to characterize the intensity and phase of terahertz pulse trains generated from nonlinear and dispersive interactions in optical fibers. We show that existing FROG retrieval algorithms are easily adapted to allow the retrieval of periodic pulse characteristics and, using synthetic pulse trains generated from numerical simulations, we demonstrate how FROG can differentiate between periodic pulse trains with fundamentally different intensity and phase characteristics, yet qualitatively similar autocorrelation functions and spectra. Experimental results are presented for the FROG characterization of a 0.3-THz sinuso…
Singularity analysis and integrability for a HNLS equation governing pulse propagation in a generic fiber optics
2006
Abstract Taking into account many developments in fiber optics communications, we propose a higher nonlinear Schrodinger equation (HNLS) with variable coefficients, more general than that in [R. Essiambre, G.P. Agrawal, Opt. Commun. 131 (1996) 274], which governs the propagation of ultrashort pulses in a fiber optics with generic variable dispersion. The study of this equation is performed using the Painleve test and the zero-curvature method. Also, we prove the equivalence between this equation and its anomalous integrable counterpart (the so-called Sasa–Satsuma equation). Finally, in view of its physical relevance, we present a soliton solution which represents the propagation of ultrasho…
Stable coupled conjugate solitary waves in optical fibers.
1998
Four-wave mixing of an intense continuous-wave pump beam with an ultrashort soliton signal in an optical fiber is theoretically analyzed. A novel class of stable two-color coupled solitary waves is found. These vector parametric solitons represent the optimal frequency conversion of an ultrashort pulse. © 1998 Optical Society of America.
Theory of Raman effect on solitons in optical fibre systems: impact and control processes for high-speed long-distance transmission lines
2004
We examine the effects of stimulated Raman scattering on ultra-short pulses propagating in optical fibre systems. We demonstrate that the existing theories for the Raman-induced soliton self-frequency shift give consistent results in a restricted domain of pulse width which excludes important practical applications to high-speed soliton transmission systems. We present a general theory for the soliton self-frequency shift (SSFS), which applies to any pulse whose spectral bandwidth lies within the third-order telecommunication window. We also show that the harmful impact of the SSFS in high-speed long-distance transmission lines can be suppressed by use of filters whose central frequency is …
Precision measurement of spin-dependent interaction strengths for spin-1 and spin-2 87Rb atoms
2006
We report on precision measurements of spin-dependent interaction-strengths in the 87Rb spin-1 and spin-2 hyperfine ground states. Our method is based on the recent observation of coherence in the collisionally driven spin-dynamics of ultracold atom pairs trapped in optical lattices. Analysis of the Rabi-type oscillations between two spin states of an atom pair allows a direct determination of the coupling parameters in the interaction hamiltonian. We deduce differences in scattering lengths from our data that can directly be compared to theoretical predictions in order to test interatomic potentials. Our measurements agree with the predictions within 20%. The knowledge of these coupling pa…
OPCPA using beams shaped by diffractive optical elements
2011
Optical parametric chirped pulse amplification (OPCPA) is becoming a widely accepted technique for the generation of high energy ultrashort laser pulses. Flat-top spatial profile pump beams can improve the efficiency of OPCPA, however such beams can be energetically costly to generate and are difficult to implement for low pump energy systems. An elegant and efficient solution to the generation of flat-top spatial profiles is the use of a diffractive optical element (DOE), however these devices distort the geometric phase of the pulses, possibly making them unsuitable for phase coherent interactions such as OPCPA.
Perspectives of XUV sources development on LASERIX facility, ILE, and ELI
2009
In this paper we present the perspectives of the development of the XUV laser sources using High-power laser facilities. We focus our paper on the present statuts of the LASERIX facility and especially its role in the development of the XUV laser sources considering the French "Institut de la Lumiere Extreme" (ILE) and the potential European project Extreme Light Infrastructure (ELI).
Experimental investigations of backward transition radiation characteristics in extreme ultraviolet region
2011
ABSTRACT This report summarizes the results of an experiment dedicated to the observation of backward transition radia-tion in the EUV spectral region. This radiation was ge nerated by an 855MeV electron beam at a molybdenumtarget. The radiation characteristics in the EUV region are compared to those in the optical region. It wasshown that the radiation measured in the EUV region was more intense than theoretically predicted. As aresult the EUV radiation yield seems to be suci ent for standard beam prole diagnostics.Keywords: EUV, Transition radiation, Beam diagnostics 1. INTRODUCTION Transverse prole diagnostics in mo dern electron linear accelerators as F ELs or injector linacs is mainl…