Juan Jose Gonzalez

Lasing in Ne-like S and other new developments in capillary discharge ultrashort wavelength lasers

We report our most recent progress in the development of capillary discharge soft x-ray lasers. This includes the first observation of discharge-pumped ultrashort wavelength lasing in a material that is solid at room temperature (S), and preliminary results of discharges in Ca. Excitation by a capillary discharge of S vapor generated by discharge ablation of a solid target resulted in amplification in Ne-like S at 60.8 nm with a gain-length product of 7.5. Overheating of the electron temperature respect to steady-state ionization conditions and transient population effects significantly increased the gain above the steady state-value. The results of two-dimensional near-field and far-field imaging of a saturated table-top Ne-like Ar laser and the measurement of its spatial coherence as a function of amplifier length are also reported and compared with model calculations. The generation of a capillary discharge plasma waveguide is to be used in combination with ultrashort pulse laser excitation for the generation of a new kind of efficient collisional soft x- ray laser is discussed.

Generation of plasma columns for shorter-wavelength capillary discharge soft x-ray lasers utilizing a high-power Blumlein generator

Capillary discharge plasmas were generated with current pulses up to 200 kA and 10 - 90% rise time of about 10 ns using a water dielectric Blumlein generator. Time resolve spectra and pinhole images of the plasma columns generated in ceramic capillaries are presented. The data indicates that the plasma obtain in ceramic capillaries are hotter than those generated in polyacetal capillaries. The maximum degree of ionization, plasma dimensions and time evolution are in general agreement with model computations and show the generation of plasma columns 250 - 300 micrometers diameter with temperatures is congruent to 250 eV.

Tabletop soft x-ray lasers by fast discharge excitation

We review the progress in the development of ultrashort- wavelength lasers based on discharge excitation. The observation of large soft x-ray amplification in Ne-like Ar at 46.9 nm in a capillary discharge created plasma [Phys. Rev. Lett. 77, 1476, (1996)] have opened a new path for the development of compact and practical soft x-ray lasers. These results have shattered the earlier perception that discharge- created plasmas are insufficiently stable and uniform for soft x-ray lasing. We report results of a detailed characterization of the capillary discharge Ne-like Ar laser, that include near-field and far-field images of the laser output and the measurement of its spatial coherence. The recent demonstration of lasing in Ne-like S at 60.8 nm in material ablated from a solid target by a discharge is also discussed.

Saturated Table-Top Soft X-Ray Lasers by Discharge Excitation

We review the rapid progress in the development and study of compact and practical ultra-short wavelength lasers based on discharge excitation. The field has advanced from the first observation of large soft x-ray amplification in a capillary discharge created plasma1, to the demonstration of an extremely compact saturated laser at 46.9 nm 2. Other papers in these Proceedings and references therein address the recent progress in the development and application of laser pumped soft x-ray lasers3–5.

Saturation behavior of a discharge pumped soft X-ray amplifier

In summary, gain length products up to 14 have been measured in the J=0-1 line of Ne-like Ar in a capillary discharge. The maximum gl product was obtained in 15 cm long plasma columns, length above which the intensity is observed to saturate. This is the first time a discharge pumped XUV laser amplifier is operated with a gain length product approaching saturation.