Compressing and focusing a short laser pulse by a thin plasma lens - art. no. 026411

We consider the possibility of using a thin plasma slab as an optical eleme nt to both focus and compress an intense laser pulse. By thin we mean that the focal length is larger than the lens thickness. We derive;analytic form ulas for the spot size and pulse length evolution of a short laser pulse pr opagating through a thin uniform plasma lens. The formulas are compared to simulation results from two types of particle-in-cell code. The simulations give a greater final spot size and a shorter focal length than the analyti c formulas. The difference arises from spherical aberrations in the lens wh ich lead to the generation of higher-order vacuum Gaussian modes. The simul ations also show that Raman side scattering can develop. A thin lens experi ment could provide unequivocal evidence of relativistic self-focusing.