Resonance-affected High-Order Harmonic Emission from Atomic and Molecular Chromium Laser-Induced Plasmas

The resonance enhancement of single-harmonic emission during the propagation of ultrafast pulses through chromium-contained plasmas is reexamined. We compare atomic (Cr) and molecular (Cr2O3, Cr3C2) plasmas to demonstrate a distinction in the enhancement factor of the single harmonic. We show how, in the case of 806 nm pump, the enhancement of the 29th harmonic (λ=27.8 nm) in Cr-contained plasma depends on the constituency of the plasma components at different conditions of target ablation. The application of tunable (1280–1440 nm) radiation allows the demonstration of notable variations of single harmonic (46 to 49 orders) enhancement using a two-color pump of Cr-contained plasma.