Far-field, near-field and interference patterns imaging in LiF crystals from a 46.9-nm capillary discharge pumped soft-x-ray laser

The recent progress in the development of the tabletop soft x-ray lasers pumped by capillary discharges has opened the possibility of the widespread use of these coherent sources for applications. In this paper, we present the latest results achieved in our laboratory concerning the optimization of a 46.9nm capillary discharge pumped soft x-ray laser and the imaging of the laser beam on Lithium Fluoride (LiF, films), which appears to be a new promising x-ray detector. The use of LiF allows a high spatial resolution (smaller than 1μm on large areas, high-contrast imaging and simple manipulation. The laser, which is pumped by 18-20kA, 150-180ns long current pulses at a repetition rate of 0.1 Hz, is produced in 3.2mm diameter up to 45cm length alumina capillary tubes filled with Ar at the initial gas pressure of 300-600mTorr. At the capillary lengths examined, the laser is operating in the saturation regime giving a output energy of about 300μJ per pulse and high coherence degree.