Controlling single harmonic enhancement in laser-produced plasmas

摘要

We compare the plasma emission and harmonic generation spectra in the cases of resonance enhancement of single harmonic using various laser-produced plasmas. The analysis of these spectra showed that the enhancement of harmonics depended on the oscillator strengths of the nearby ionic transitions rather than the plasma emission transitions. To prove it, we used the tunable source of mid-infrared radiation from an optical parametric amplifier (1200-1600 nm) and the fixed wavelength source (810nm) of femtosecond pulses. The comparison of resonantly enhanced and featureless plateaulike harmonic spectra from different laser-produced plasmas, as well as their plasma emissions, confirmed this assumption.