Control of the properties and diagnostics of a dense femtosecond plasma formed from modified targets

Abstract

It was found that modification of the physical properties of the surface layer of a target makes it possible to control, effectively and within a wide range, the characteristics of a femtosecond laser plasma (temperature, degree of ionisation, emissivity, and nonlinear-optical susceptibility) at moderate intensities of 10 15^1 0 16 W cm À2 , which are optimal for promising laser-plasma femtosecond technologies. The targets used in an experimental investigation were periodic structures (gratings), ultrafine freely suspended films, and porous materials. Potential applications of such targets at intensities above 10 17 W cm À2 were considered. R V Volkov, V M Gordienko, M S Dzhidzhoev, M A Zhukov, P M Mikheev, A B Savel'ev, A A Shashkov Control of the properties and diagnostics of a dense femtosecond plasma formed from modified targets R V Volkov, V M Gordienko, M S Dzhidzhoev, M A Zhukov, P M Mikheev, A B Savel'ev, A A Shashkov

Nuclear processes in dense plasma produced by femtosecond laser pulses at sub-relativistic intensities

“…M T h ,keV 12 16 The results of TOF ion measurements also support hard X-ray yield measurements. Lets start by considering results for the position A of the TOF spectrometer.…”

“…We used dye femtosecond laser system [12] provided us with 200 fs, up to 1 ml, 610 nm laser pulses at 1 Hz repetition rate. Tight focusing provided us with intensity up to 50 PW/cm 2 at intensity contrast ratio better than 10 5 .…”

<title>Hard x-ray and high-energy proton production under femtosecond laser interaction with free liquid surface</title>

“…To create plasma at the target we use the p-polarized radiation of femtosecond dye-laser system (200 fs, 616 nm, 300 uJ, intensity contrast 1O) [4]. Radiation of the laser system was focused at the target surface by aberration free objective with a 6 cm focal length at 45° angle of incidence that allowed to obtain 5 micrometers diameter of the focal spot.…”

“…Such plasma has unique properties and can be used as a source of fast electrons, ions and short hard x-ray pulses [1,2]. Today many experiments on femtosecond laser plasma formation at different targets were carried out (solid targets [3], porous targets [4], clusters [5] and other).…”

<title>Generation of nonclassical light by electron beams</title>

“…This kind of medium can be obtained for example by the evaporation of the matter surface by the power short light pulse. 13 The alternative approach is to use an electron beam with considerably small concentration of electrons. This beam have to be bunched in a certain way so that a system of consecutive electron mirrors will be formed.…”