Hard x-ray emission in high intensity femtosecond laser–target interaction

Abstract

Hard x-ray spectra (10–100 keV) created in high contrast, 400 fs, laser pulse interaction with solid targets, have been studied for laser intensities in the 1017–1019 W/cm2 range. The target atomic numbers (Z) extended from Z=13 to Z=73. The measured conversion efficiency at Ag Kα emission line was 10−3% at 5×1018 W/cm2. It has been confirmed that the hot electron temperature increased as (Iλ2)1/3 and the fraction of laser energy in hot electrons follows scaling law of (Iλ2)3/4.

Forward Ion Acceleration in Thin Films Driven by a High-Intensity Laser

“…They acquire an energy e e from the laser pulse which can be evaluated from energy balance: n e e e c ഠ hI, where n e is the electron density of small size preformed plasma and coefficient h defines the efficiency of laser-energy conversion into the high-energy electrons. For laser intensities in the range of 10 17 3 3 10 18 W͞cm 2 we estimate h in a range from a few percent to 15%, in accordance with previous measurements [20] in similar experimental conditions.…”

Study of X-Ray Emission Enhancement via a High-Contrast Femtosecond Laser Interacting with a Solid Foil

“…Imaging plate is used as detector in spectrometer and also used for electron angular distribution measurement. The x-ray emission size is measured by the knifeedge imaging technique [6]. The FWHM of fitted Gaussian function shows source size ~10 µm in 400 nm laser irradiation, implying no evident plasma expansion in this case.…”

Short-Pulse Laser-Produced Plasmas

“…electronic satellites. Time duration of these kilovolt emissions have been studied with a sub-ps resolution streak camera [77,78], and conversion efficiencies have been determined for more energetic x-rays [79]. Spectroscopy of ultrafast plasmas has been performed with contrast-clean laser pulses obtained through frequency doubling [80,81] and tamped Al-tracer layer-targets [82].…”