Lasing at 52.9 nm in Ne-like chlorine and steps towards shorter wavelength capillary discharge lasers

Abstract

Significant advances have been obtained in the past few years in the development of soft x-ray lasers. Both, laser-pumped and discharge-pumped schemes have been successfully demonstrated. In particular, a very compact capillary discharge laser has been demonstrated to deliver an average power of several mW in the 46.9 nm line of Ne-like Ar. The work presented in this thesis, that was motivated by the possibility extending the very practical discharge excitation scheme to other short wavelengths laser transitions, can be divided in two parts. The first resulted in the successful demonstration of amplified spontaneous emission in the 3 p ¹Sₒ - 3s ¹P₁ transition of Ne-like Cl at 52.9 nm. Laser pulses of ~1.5 ns duration with energies up to 10 μJ and a beam divergence 4 mrad were obtained at repetition rates of 0.5 - 1 Hz. This new 23.4 eV table top laser is of particular interest for applications requiring high peak fluxes of photons with energy slightly below the He photoionization threshold. The results discussed in the second part of this thesis represent the first steps necessary for the development of a discharge-pumped Ni-like Cd laser at 13.2 nm. A room temperature source of atomically pure Cd vapor was developed and used to inject Cd into the capillary channel, where it was excited by a fast high current pulse to produce a hot dense plasma. The first spectroscopic data of a capillary discharge plasma containing Ni-like Cd ions (Cdₓₓᵢ) was obtained and analyzed. These results can be of use in future works when trying to develop a collisionally excited discharge-pumped Ni-like Cd laser.