<title>Advances in capillary discharge soft x-ray laser research</title>

Abstract

This paper gives an overview of recent soft x-ray laser research at Colorado State University. Progress related to capillary discharge source development includes the observation ofemission from the 13.2 nm laser line ofNickel-like Cd in a plasma column generated by a high power capillary discharge. This result suggests it might be possible to extend capillary discharge lasers to significantly shorter wavelengths. In another approach to the generation of coherent soft x-ray radiation we analyzed the possibility of amplifying high order harmonic pulses in a discharge-pumped amplifier. The study of the already well-characterized 46.9 nm Ne-like Ar laser was extended with new spatial coherence and laser wavefront measurements, in work conducted in collaboration with U. California Berkeley and U. of Paris-Sud groups. In the field of applications, we have extended our previous results of plasma interferometry with a table-top laser to plasma densities up to 0.9 x 1021 cm3 Sequences of soft x-ray laser interferograms of plasmas generated by a Nd-YAG laser at intensities between

Weakly ionized plasma flash x-ray generator and its distinctive characteristics

“…Recently, soft x-ray lasers have been produced by a gas-discharge capillary, [13][14][15][16] and the laser pulse energy substantially increased in proportion to the capillary length. These kinds of fast discharges can generate hot and dense plasma columns with aspect ratios approaching 1000:1.…”

Magnetohydrodynamics control of capillary Z-pinch discharge by using a triangular current pulse for lasing a H-like N recombination soft x-ray laser

“…However, it is difficult to realize lasing a SXRL because the pumping power required to amplify a collisional excitation SXRL is inversely proportional to its wavelength and thus it requires a large system. [10][11][12][13][14][15] However, there is no demonstration of lasing SXRLs of these wavelengths up to saturation because it is still difficult to generate a highly uniform long plasma column with a several or a several tens cm length. In 1985, using an ultrashort pulsed laser for collisional or recombination excitation, a SXRL at a wavelength of around 20 nm has been demonstrated in Lawrence Livermore Laboratory and Princeton Plasma Physics Laboratory, respectively.…”

Observation of emission process in hydrogen-like nitrogen Z-pinch discharge with time integrated soft X-ray spectrum pinhole image

“…14 Meanwhile, the possibility of SXRL at shorter wavelengths has also been investigated resulting in the lasing at 13.2 nm Ni-like Cd and 18.2 nm H-like C recombination lines by ablative capillary discharge. [15][16][17][18][19] As a consequence, a gas discharge H-like N recombination SXRL (Fig. 1) at the wavelength of 13.4 nm (EUV) has been proposed, 20 and the observation of He and Lyman series radiation has been reported thus far.…”