117 research outputs found
Adaptive pulse compression for transform-limited 15-fs high-energy pulse generation
Includes bibliographical references (page 589).We demonstrate the use of a deformable-mirror pulse shaper, combined with an evolutionary optimization algorithm, to correct high-order residual phase aberrations in a 1-mJ, 1-kHz, 15-fs laser amplifier. Frequency resolved optical gating measurements reveal that the output pulse duration of 15.2 fs is within our measurement error of the theoretical transform limit. This technique significantly reduces the pulse duration and the temporal prepulse energy of the pulse while increasing the peak intensity by 26%. It is demonstrated, for what is believed to be the first time, that the problem of pedestals in laser amplifiers can be addressed by spectral-domain correction
Experimental and theoretical study of supercontinuum generation from a short length of microstructure fiber
Angiitis with Nodule Formation, Vasomotor Instability and Secondary Cutis Laxa11From the University of Southern California School of Medicine, Department of Medicine (Doctor Winsor) and Section of Dermatology (Doctor Obermayer), Los Angeles, California.
Measurement of the intensity and phase of supercontinuum from an 8âmmâlong microstructure fiber
Propriétés de cohérence de spectres de supercontinuum générés dans les fibres à cristaux photoniques
Crossâcorrelation frequency resolved optical gating analysis of broadband continuum generation in photonic crystal fiber: simulations and experiments
Numerical simulations are used to study the temporal and spectral characteristics of broadband supercontinua generated in photonic crystal fiber. In particular, the simulations are used to follow the evolution with propagation distance of the temporal intensity, the spectrum, and the cross-correlation frequency resolved optical gating (XFROG) trace. The simulations allow several important physical processes responsible for supercontinuum generation to be identified and, moreover, illustrate how the XFROG trace provides an intuitive means of interpreting correlated temporal and spectral features of the supercontinuum. Good qualitative agreement with preliminary XFROG measurements is observed. © 2002 Optical Society of America.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Shaped-pulse optimization of coherent emission of high-harmonic soft X-rays
Includes bibliographical references (page 166).When an intense laser pulse is focused into a gas, the light-atom interaction that occurs as atoms are ionized results in an extremely nonlinear optical process-the generation of high harmonics of the driving laser frequency. Harmonics that extend up to orders of about 300 have been reported, some corresponding to photon energies in excess of 500 eV. Because this technique is simple to implement and generates coherent, laser-like, soft X-ray beams, it is currently being developed for applications in science and technology; these include probing the dynamics in chemical and materials systems and imaging. Here we report that by carefully tailoring the shape of intense light pulses, we can control the interaction of light with an atom during ionization, improving the efficiency of X-ray generation by an order of magnitude. We demonstrate that it is possible to tune the spectral characteristics of the emitted radiation, and to steer the interaction between different orders of nonlinear processes
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