Ultrarelativistic nanoplasmonics as a route towards extreme-intensity attosecond pulses

Abstract

Marklund, M., Sergeev, A. (2011) Ultrarelativistic nanoplasmonics as a route towards extreme-intensity attosecond pulses.Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, 84(4) The generation of ultrastrong attosecond pulses through laser-plasma interactions offers the opportunity to surpass the intensity of any known laboratory radiation source, giving rise to new experimental possibilities, such as quantum electrodynamical tests and matter probing at extremely short scales. Here we demonstrate that a laser irradiated plasma surface can act as an efficient converter from the femto-to the attosecond range, giving a dramatic rise in pulse intensity. Although seemingly similar schemes have been described in the literature, the present setup differs significantly from the previous attempts. We present a model describing the nonlinear process of relativistic laser-plasma interaction. This model, which is applicable to a multitude of phenomena, is shown to be in excellent agreement with particle-in-cell simulations. The model makes it possible to determine a parameter region where the energy conversion from the femto-to the attosecond regime is maximal. Based on the study we propose a concept of laser pulse interaction with a target having a groove-shaped surface, which opens up the potential to exceed an intensity level of 10 26 W/cm 2 and observe effects due to nonlinear quantum electrodynamics with upcoming laser sources.

On the physics of electron ejection from laser-irradiated overdense plasmas

“…For E i > 0, the electric force accelerates electrons in the -y direction, allowing them to reach speed v y տ À 1 as soon as a 0 > 1. 32 The v  B i force is then directed towards the þx direction, so that it pushes electrons which concentrate and form a sharp density peak into the plasma. This is shown in Fig.…”

“…In addition, electron ejection from the front surface is not well understood: several numerical studies report on the subject [27][28][29][30] but so far, no theory has been developed in order to explain and predict electron ejection. Some models have been developed in the context of HHG in order to describe the dynamics of the plasma surface, 31,32 but these models are not useful for describing electron emission because of the strong hypothesis that they rely upon.…”

Prospects and limitations of wakefield acceleration in solids

“…This results in an amplitude restriction on the reflected pulse, as it never can exceed that of the incoming radiation. Moreover, the amplitude of the X-ray burst, as described by RES, can be further increased by using a groove-shaped target, 6 reaching an increased range of relativistic amplitudes a 0 $ 10 for parameters available at current laser facilities.…”

“…The relativistic electron spring model 6,7 (RES) is one suggestion of a method which may provide a source of high harmonics, which is suitable in realizing an X-ray driven wakefield accelerator. The RES model is capable of describing the interaction of laser light with moderately overdense plasmas (1 S < 10, where S ¼ n e =a 0 n c and n e is the electron density).…”

Pseudospectral Maxwell solvers for an accurate modeling of Doppler harmonic generation on plasma mirrors with particle-in-cell codes

“…For intensities such as the ones achieved by 100TW/PW lasers, the very high laser electric field drives periodic oscillations of the plasma mirror surface at relativistic velocities. These periodic oscillations induce a periodic distortion of the reflected field by Doppler effect [8][9][10][11], which is associated in the frequency domain to a comb spectrum made of high harmonics of the incident laser frequency.…”