High-Order Harmonic Generation From Laser- Ablated Plasma Plume Pumped by Femtosecond Laser Pulse.

We have demonstrated a generation of 71st harmonic at a wavelength of 11.20 nm using low ionized vanadium ions in a laser ablation plume as a nonlinear medium. The conversion efficiency of this harmonic was about 0.8x10-6. Further the 61st harmonic at a wavelength of 13.03 nm with conversion efficiency of 2.6x10-6 have been obtained using the laser ablation titanium plume. Such high harmonics generation appears to an interaction between a femtosecond laser pulse and double charge ions. [ABSTRACT FROM AUTHOR]