The study of electron impact transient collisional excitation laser

We observed substantial amplification of the transition of 4d → 4p, J=0 → 1 (the transition from (3d3/2, 4d3/2)0 to (3d3/2, 4p1/2)1) of the Ni-like lanthanum (La) ions at a wavelength of 8.8 nm pumped by a CPA (Chirped Pulse Amplification) Nd:Glass laser light at a wavelength of 1.053 μm with a pumping energy of 18 J. The experimental gain coefficient and the achieved gain-length product was 14.5 cm-1 and 7.7, respectively. In this experiment, the pumping laser pulse consisted of a pre-pulse with a duration of 200 ps and a 7ps-duration main pulse, separated by 250 ps. This configuration generated a pre-formed plasma with short scale length and made it possible by the main pulse to generate population inversion in high density region. (author)