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B Cros

Publications and source records attributed to B Cros.

8 recordsLinked to original sources
PubMed2005

Absolute time-resolved x-ray laser gain measurement.

We present the first direct measurement of the time evolution of the gain of a soft x-ray laser amplifier. The measurement is based on the injection of a seed pulse, obtained by high-order harmonic generation, into an x-ray laser medium. Strong amplification occurs when the seed pulse is synchronized with the gain period. By precisely varying the delay between the x-ray laser plasma creation and the seed pulse injection, the actual temporal evolution of the soft x-ray amplifier gain is obtained with a subpicosecond resolution.

Journal Article↗
PubMed2003

Demonstration of a collisionally excited optical-field-ionization XUV laser driven in a plasma waveguide.

We describe the first demonstration of a collisionally excited optical-field-ionization laser driven within a waveguide. Lasing on the 4d(9)5d-4d(9)5p transition at 41.8 nm in Xe8+ was observed to be closely correlated to conditions under which the pump laser pulses were guided well by a gas-filled capillary discharge waveguide. Simulations of the propagation of the pump laser radiation show that gain was achieved over essentially the whole 30 mm length of the waveguide.

Journal Article↗
PubMed2002

Eigenmodes for capillary tubes with dielectric walls and ultraintense laser pulse guiding.

The properties of the eigenmodes of a capillary tube are examined in the context of ultrashort intense laser pulse guiding. The dispersion relation for the eigenmodes of a cylindrical hollow waveguide is derived and the family of eigenmodes EH(nus) is shown to be a solution of the wave equation up to the first order under the condition k(0)a >>1, where k(0) is the light wave number and a the capillary tube radius. The expressions of the fields for the eigenmodes are given at zero and first order of a small parameter equal to the ratio of the perpendicular to longitudinal wave number and the absorbed intensity at the wall is estimated.

Journal Article↗
PubMed2001

Nonlinear propagation of short intense laser pulses in a hollow metallic waveguide.

The propagation of a short intense laser pulse in the femtosecond range in a hollow metallic waveguide gives rise to heating of the metallic wall. The temperature of the degenerate electron gas in the wall is increased during the pulse duration and this heating affects the propagation and dissipation of the laser pulse. Analytical and numerical analysis shows that, as the dissipation is increased, the leading edge of the pulse decreases more slowly than the rear, resulting in a pulse shortening.

Journal Article↗
PubMed1994

[Invasions of Paederus sabaeus (Coleoptera Staphylinidae) in central Africa. 1. Entomological and epidemiological aspects].

In May 1993, at the end of the rainy season, outbreaks of Paederus sabaeus (Coleoptera, Staphylinidae) were recorded in Brazzaville (Congo), Kinshasa (Zaire), Franceville and Libreville (Gabon) and even in Bangui (CAR) at the North of the equator. A short review of previous outbreaks in Africa and on vesicant substances is given by the authors. These beetles are attracted to neon lights and they rest on the walls or on the skin of the occupants. When the insects are crushed on the bare skin their haemolymph liberate pederine and related vesicant components which provocate dermatitis. The insects disappeared spontaneously after three to four weeks.

Animals↗