Plasma-Based Generation and Control of a Single Few-Cycle High-Energy Ultrahigh-Intensity Laser Pulse

A laser-boosted relativistic solid-density paraboloidal foil is known to efficiently reflect and focus a counterpropagating laser pulse. Here we show that in the case of an ultrarelativistic counterpropagating pulse, a high-energy and ultrahigh-intensity reflected pulse can be more effectively generated by a relatively slow and heavy foil than by a fast and light one. This counterintuitive result is explained with the larger reflectivity of a heavy foil, which compensates for its lower relativistic Doppler factor. Moreover, since the counterpropagating pulse is ultrarelativistic, the foil is abruptly dispersed and only the first few cycles of the counterpropagating pulse are reflected. Our multidimensional particle-in-cell simulations show that even few-cycle counterpropagating laser pulses can be further shortened (both temporally and in the number of laser cycles) with pulse amplification. A single few-cycle, multipetawatt laser pulse with several joules of energy and with a peak intensity exceeding ${10}^{23}{\mathrm{W}/\mathrm{cm}}^2$ can be generated already employing next-generation high-power laser systems. In addition, the carrier-envelope phase of the generated few-cycle pulse can be tuned provided that the carrier-envelope phase of the initial counterpropagating pulse is controlled.

Figure 1

The maximum amplitude of the reflected pulse $\sqrt{D^{+4}{\mathcal{R}}_s{I}_s/I^{*}}$ as a function of ${\zeta }_0$ for $a_d=130$ and $a_s=130$ (solid red line), $a_s=100$ (dashed blue line) and $a_s=80$ (dotted black line). See the text for further details.

Figure 2

Snapshots of $u=\sqrt{({\mathbf{E}}^2+{\mathbf{B}}^2)/2}$ (first row) and $n_e$ (second row) in normalized units. See the text for details.

Figure 3

(a) $E_{r,y}$ along the central axis for zero (solid black line) and $\pi /2$ (dotted red line) CEP of the source pulse. (b) $E_{r,y}$ with RR effects (solid black line) and with a preplasma on the front surface of the foil (dashed red line). (c) Power contained in a spot with $1\lambda$ radius centered on the axis. (d) $|E_{r,y}(k_x)|$ (solid black line) and the corresponding quantity for a Gaussian pulse with two (dotted red line) and three (dashed blue line) cycles FWHM of the field profile. The inset shows a zoom of the main peak region.