Polarization gating using cross-polarized wave generation with multicycle lasers to produce isolated attosecond pulses in overdense media

A method to generate a polarization gate for multicycle laser pulses is presented. We study the performance of a pulse with time-dependent polarization to produce a single attosecond pulse after its interaction with an overdense plasma. The polarization gate is generated through the use of cross-polarized wave generation in a single BaF sub(2) crystal combined with a dispersive medium. Numerical simulations demonstrate that using the polarization gate, the number of pulses in the attosecond train can be reduced. With this method a single attosecond pulse can be isolated by filtering the high harmonic orders in the reflected spectrum. The dependence of the ellipticity curve on the dispersion introduced is studied as well as its influence in the size of the polarization gate.