High-order harmonic generation in Bi and Pb plasmas

We report the high-order harmonic generation of 65 fs, 800 nm pulses and tunable pulses from optical parametric amplifier in the plasmas produced on the surfaces of the materials belonging to the sixth period of the periodic table (Bi and Pb). The optimization of the fluence of heating pulses, the delay between heating and driving pulses, and the distance from target to the propagating femtosecond pulses allowed generation of harmonics up to the 57th order. The two-color pump-induced harmonic generation and application of near infrared pulses for sum and difference frequency generation in these plasmas are reported.