Experimental Study of the Gain Dependence on Driving Laser Pulse Leading Edge Duration

Abstract

AbstractWe present the preliminary results of the experiment focused on the generation of the Ne-like Ti XUV laser radiation (32.6 nm). Within the experiment, the two-pulse scheme (pre-pulse and main pulse) was adopted. The population inversion is produced between 2p53p and 2p53 s fine-structure levels of Ne-like ions, through electron collisional excitation from the Ne-like ground state 2p6. The inversion is maintained by strong radiative dipole decay from the 3 s levels back to the ground state while the upper 3p levels are metastable with respect to this process. Under appropriate plasma conditions, the strongest population inversion is generated (due to the highest monopole electron excitation rate from the ground state) for (2p51/23p1/2) (J = 0) → (2p51/23s1/2) (J = 1) transition in Ne-like Ti, corresponding to the wavelength of 32.62 nm. The intensity and beam profile emitted by this type of XRL strongly depends on the density profile of the amplifying plasma, as the largest population inversion on the J = 0 → 1 transition occurs at high electron densities. Hence various laser beam parameters (i.e. intensity ratio, delay between pulses, etc.) were investigated. The main focus was to study the dependence between the XRL and the pulse duration of the driving laser beam, especially the leading edge of the pulse.