Dependence on pulse duration and foil thickness in high-contrast-laser proton acceleration

Abstract

Experimental measurements of proton acceleration with high intensity and high-contrast short laser pulses have been carried out over an order of magnitude range in target thickness and laser pulse duration. The dependence of the maximum proton energy with these parameters is qualitatively supported by two-dimensional particle-in-cell simulations. They evidence that two regimes of proton acceleration can take place, depending on the ratio between the density gradient and the hot electron Debye length at the rear target surface. As this ratio can be affected by the target thickness, a complex interplay between pulse duration and target thickness is observed. Measurements and simulations support unexpected variations in the laser absorption and hot electron temperature with the pulse duration and laser intensity, for which density profile modification at the target front surface is the controlling parameter.

Brunel-Dominated Proton Acceleration with a Few-Cycle Laser Pulse

“…Laser-driven ion sources are particularly interesting in medicine for hadrontherapy [9,10] and in science for plasma radiography [11], heating particles for fast ignition [12], and warm dense matter studies [13,14]. The properties of the ion beam also provide useful information in situ about the interaction conditions, including laser focusing and temporal contrast [15,16].…”

Enhanced target normal sheath acceleration of protons from intense laser interaction with a cone-tube target

“…can already be achieved by using current laser facility, which indicates that the demonstrated scheme 47 where a near-critical low-density foam is being added to a foil and another PIC simulation 48 with laser duration near 30fs. The blue (dark gray) solid squares are for testing, which verified the accuracy of our 2D PIC simulation code.…”

“…PIC simulation results from other target design for similar parameters are also shown. 47,48 In these cases, the proton energy can be increased compared to the pure foil case, but is still under the scaling for the cone-tube target, as shown in Fig. 5.…”

Energy-scalable temporal cleaning device for femtosecond laser pulses based on cross-polarized wave generation

“…Requiring moderate intensity (10 12 W/m 2 ), XPW filtering is usually implemented in a double-CPA scheme 27 and is commonly used to improve the contrast of TW-and PWclass lasers. 5,[28][29][30][31] Commercial set-ups are currently provided by Thales Optronique SA 32 and Amplitude Technologies.…”