Observation of multi-pulse soft x-ray lasing in a fast capillary discharge

In this presentation we summarize the results on lasing in the soft X-ray region as obtained with ablative capillary discharges at the Ruhr-University of Bochum. During the first half-cycle of the discharge the initial plasma is obtained from ablated wall material (polyacetal); in the second half-cycle a chain of hot plasma spots is produced in the neck regions of a m = 0 instability. Fully stripped carbon ions stream into the cold plasma outside the necks, and charge exchange with CIII ions results in population inversion between the n = 3 and n = 2 levels of CVI and thus in lasing at 18.22 nm. Modulation of the inner wall or of the return conductor influences the wavelength of the instability and via the number of inversion layers also the lasing spike. Its duration is measured to about 400 ps. The relevant charge exchange processes are also demonstrated with colliding laser produced plasmas.

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“…In the meantime, successful operation of similar systems has been reported by a number of groups, e.g. [8,9,10].…”

Section: Introductionmentioning

confidence: 93%

X-ray lasing in ablative capillary discharges

Kunze

Ellwi²,

Andreić

2006

Czech J Phys

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“…8,9 Discharge-excited XUV lasers via the production of a plasma column, have also been demonstrated. [10][11][12] An XUV laser operating at 46.9 nm based on a fast capillary discharge has been reported as a short wavelength light source. 10 The operation of this argon-gas-based XUV laser at 46.9 nm, in a fast pulsed capillary discharge laser system, however, requires a large capacitor power supply ͑typically a Marx bank configuration͒ to produce high peak current and a differential vacuum pumping system.…”

Section: Introductionmentioning

confidence: 99%

Microdischarge extreme ultraviolet source with alkali metal vapor for surface morphology application

Higashiguchi

Terauchi

Ôtsuka

et al. 2011

Journal of Applied Physics

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We have characterized a discharge-produced potassium plasma extreme ultraviolet (XUV) source. Potassium ions produced strong broadband emission around 40 nm with a bandwidth of 8 nm (full width at half-maximum). By comparison with atomic structure calculations, the broadband emission is found to be primarily due to 3d–3p transitions in potassium ions ranging from K2+ to K4+. The current-voltage characteristics of the microdischarge suggest that the source operates in a hollow cathode mode and consequently the emitting ions may be localized on the potassium electrode surface at the hole into the capillary. To understand the spectral behavior from the potassium plasmas we compared the spectra from the discharge-produced plasma with that from a laser-produced plasma. The spectra from the different (electric and laser) plasmas at the same electron temperature (12 eV) were almost the same. This compact capillary XUV source with a photon energy of 30 eV is a useful XUV emission source for surface morphology applications.

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“…However, in spite of the big efforts, it is not clear up to now which one of the basic processes and experimental conditions are critical for the achievement of the lasing effect. For this reason, only very recently three independent groups [2,3,4] demonstrated the gain coefficient sufficient for the 46.9 nm lasing in Ne-like Ar inside a capillary discharge produced plasma.…”

Section: Introductionmentioning

confidence: 99%

Role of the wall ablation in the operation of a 46.9 nmAr capillary discharge soft x‐ray laser

Ritucci¹,

Tomassetti

Reale

et al. 2003

Contrib. Plasma Phys.

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A capillary discharge pumped soft x-ray laser operating at 46.9 nm on the 3p−3s transition of the Ne-like Ar has been realized by pumping the active medium with a relatively slow current pulse (dI/dt ≈ 6·10 11 A/s). In order to study the role of the ablation in the production of the laser effect, the intensity of the amplified 46.9 nm line has been investigated using the same pumping current pulses in the plastic (polyacetal) and ceramic (Al2O3). We showed that the ablation of the capillary walls is unfavorable both for the compression and stability of the plasma and consequently for the soft x-ray laser production. The amplification and lasing effects are observed only in the ceramic channel. The measurements of the line intensity at 46.9 nm showed the lasing with a gain-length product of ≈ 9, a laser pulse energy of ≈ 5 µJ, a pulse duration of 1.3 ns and a beam divergence of ≈ 3.5 mrad. In addition, effect of the scaling of the time of lasing with the initial plasma diameter was demonstrated experimentally and compared with a one-dimensional MHD model.

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Observation of multi-pulse soft x-ray lasing in a fast capillary discharge

Cited by 55 publications

References 5 publications

X-ray lasing in ablative capillary discharges

X-ray lasing in ablative capillary discharges

Microdischarge extreme ultraviolet source with alkali metal vapor for surface morphology application

Role of the wall ablation in the operation of a 46.9 nmAr capillary discharge soft x‐ray laser

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