Obtaining an X-ray laser emission from plasmas, created and
driven by an intense IR laser, has been pursued at the Laboratoire
de Spectroscopie Atomique et Ionique (LSAI) for several years.
At present, we operate various types of X-ray lasers driven
by IR laser pulses of different durations (600 ps, 100 ps, and
600 ps/1 ps). A review of different techniques used at the LSAI
to produce a strongly amplified emission using the collisional
excitation pumping is presented. In the second part of this
paper, to illustrate the potential of the X-ray lasers for
applications, we present the main results obtained with an X-ray
laser emitting at 21.2 nm in a study of surface defects of a
niobium cathode, induced by strong electrical fields. We also
describe a novel imaging interferometry device using an X-ray
laser as a source and designed as a tool for high-resolution
diagnostic of dense plasmas.