Second‐harmonic emission from laser‐plasma interactions

We have systematically investigated the second‐harmonic (2ω) emission spectrum from 1.06‐μm laser‐plasma interactions. Experimental data on the dependence of 2ω spectrum, especially its broadness and complexity, on laser irradiation intensity, incidence angle, and prepulse are presented. A theoretical model using linear mode conversion and parametric decay instability processes can qualitatively explain the experimental results.