Resonant and non-resonant high-order harmonic generation in the plasmas produced by 1 kHz picosecond and femtosecond pulses

We report the application of femtosecond and picosecond laser pulses for plasma formation on metal targets (Al, Cu, In, Sn) for non-resonant and resonant high-order harmonic generation using laser pulses with 1 kHz repetition rate. The resonance enhancement of single harmonics in the picosecond and femtosecond pulse induced In and Sn plasmas has been studied. These studies reveal comparable harmonic yields from both types of plasmas, which indicate that the pump fluence is of central importance for the optimal plasma formation for efficient harmonic generation.