Neon-like Argon Research Articles

Numerical optimization of the electrical characteristics of an EUV laser on 3p–3s transition in neonlike argon ions in low-inductance capillary-type discharge

Electrical characteristics of low-inductance capillary-type discharge have been determined by numerical model calculations, which ensure high efficiency of energy supply to a plasma column with an aspect ratio of 1: 100. The EUV argon laser based on this discharge provides a gain of g+ > 1 cm–1 on the operating transition and ensures single-pass spontaneous lasing with g+l > 25 (where l is the active medium length).

10.1007/s11452-008-2008-2

The evolution of the CAPEX facility and its basic diagnostics are described. The experiments carried out in the last modification of this facility accomplished with the demonstration of amplified spontaneous emission of neon-like argon (Ar8+) at the wavelength 46.88 nm. The first version of the facility, CAPEX1, operated with a plastic capillary and had a short high-power passive prepulse and an imperfect gas-filling system. In the second version, CAPEX2, a ceramic capillary was used, the prepulse amplitude was lowered, and the gas-filling system was improved. In the third, most successful version, CAPEX3, the capillary bending was reduced, a longer external prepulse was used, and the gas-filling system was further optimized. For each version, results of X-ray measurements are presented and interpreted.

Amplification of spontaneous emission of neon-like argon in a fast gas-filled capillary discharge

The evolution of the CAPEX facility and its basic diagnostics are described. The experiments carried out in the last modification of this facility accomplished with the demonstration of amplified spontaneous emission of neon-like argon (Ar8+) at the wavelength 46.88 nm. The first version of the facility, CAPEX1, operated with a plastic capillary and had a short high-power passive prepulse and an imperfect gas-filling system. In the second version, CAPEX2, a ceramic capillary was used, the prepulse amplitude was lowered, and the gas-filling system was improved. In the third, most successful version, CAPEX3, the capillary bending was reduced, a longer external prepulse was used, and the gas-filling system was further optimized. For each version, results of X-ray measurements are presented and interpreted.

毛细管放电软X射线激光中的多脉冲现象的实验验证方案

In a capillary discharge experiment for the neon-like argon lasing, we have proposed an experimental scheme to verify that the multi-spike of X-ray diode (XRD) signal is a multi-pulse laser or is a reflection of the laser pulse in the XRD. The ceramic capillary has an inner diameter of 3 mm and a length of 200 mm. At the gas pressure of 28 Pa and discharge current of 27 kA, stable lasing has been realized. The experimental results prove that the multi-spike of XRD signal is a reflection of the electromagnetic signal produced by the laser pulse in the XRD. The improved electrocircuit scheme of the XRD to minimize the reflection phenomena is also found.

Dramatic Enhancement of Optical-Field-Ionization Collisional-Excitation X-Ray Lasing by an Optically Preformed Plasma Waveguide

Dramatic enhancement of optical-field-ionization collisional-excitation x-ray lasing is achieved by using an optically preformed plasma waveguide. With a 9-mm-long pure krypton plasma waveguide prepared by using the axicon-ignitor-heater scheme, lasing at 32.8 nm is enhanced by 400 folds relative to the case without the plasma waveguide. An output level of 8 x 10(10) photon/shot is reached at an energy conversion efficiency of 2 x 10(-6). The same method is used to achieve x-ray lasing in a gas jet for the high-threshold low-gain transition at 46.9 nm in neonlike argon.

Effect of nonequilibrium ionization process on gain of neon-like argon x-ray laser

In connection with fast plasma heating in capillary discharges, transient ionization effect on the gain of J=0→1 transition (λ=46.9 nm) in optically thin neon (Ne)-like argon (Ar IX) x-ray laser has been theoretically investigated using the reduced time-dependent collisional–radiative model. Results indicate that the gain value at nonequilibrium ionization regime is significantly affected by the relaxation process of different ionization states, and fast heating enables us to obtain higher gain compared with the steady-state plasma.

Performances of Ne-like Ar Soft X-ray Laser using Capillary Z-Pinch Discharge

We have designed, fabricated and tested a soft X-ray device, which uses a capillary discharge to achieve neon-like argon lasing. The ceramic capillary has an inner diameter of 3 mm and a length of 150 mm. Lasing has been confirmed when operating the device with a current of 9 to 32 kA with a rise time of 55 ns, in an argon gas pressure range from 100 to 800 mTorr. The relation between the observation of the laser spike and occurrence of the moving striation has been studied by a series of side-view observations. The appropriate starting time of the main discharge with respect to that of the predischarge current has been studied. When the predischarge is properly applied, constant laser amplification of the gain-length product of gl=12 (g=0.8 cm-1) was obtained, with a current of 32 kA at a pressure of 400 mTorr.

Picosecond-laser-driven gas puff neonlike argon x-ray laser

We have performed short-pulse laser-irradiated gas puff target experiments to generate a neonlike argon soft-x-ray laser by using a small laser system. A high-pressure solenoid valve forms a gas column through a narrow slit that is irradiated by two laser pulses containing 10 J of energy. Strong lasing is observed on two transitions, the 3p 1S0→3s 1P1 line at 46.9 nm and the 3d 1P1→3p 1P1 line at 45.1 nm. We present results from a systematic study in which the gas puff and laser conditions were varied to optimize the x-ray-laser output from a 0.9-cm-long gas column.

Demonstration of a neonlike argon soft-x-ray laser with a picosecond-laser-irradiated gas puff target

We demonstrate a neonlike argon-ion x-ray laser, using a short-pulse laser-irradiated gas puff target. The gas puff target was formed by pulsed injection of gas from a high-pressure solenoid valve through a nozzle in the form of a narrow slit and irradiated with a combination of long, 600-ps and short, 6-ps high-power laser pulses with a total of 10 J of energy in a traveling-wave excitation scheme. Lasing was observed on the 3p (1)S(0)?3s (1)P(1) transition at 46.9 nm and the 3d (1)P(1)?3p (1)P(1) transition at 45.1 nm. A gain of 11 cm(-1) was measured on these transitions for targets up to 0.9 cm long.

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

We have designed, fabricated and tested a soft x-ray device, which uses acapillary discharge to achieve neon-like argon lasing. The ceramic capillaryhas an inner diameter of 3 mm and a length of 150 mm. When operating thedevice with a current of 16 kA and dI/dt of 517.8 A ns-1 at gas pressure of26.7 Pa, lasing has been confirmed. Multi-pulse laser output has also beenobserved with a slightly higher current of 17.5 kA, and this indicates thatthere exist several configurations suitable for the Ne-like Ar lasing duringone pinch process. This is the first observation of multi-pulse laser output.

Capillary discharge experiment for collisional excitation soft X-ray laser

The realization of a capillary discharge soft X-ray source, for soft x ray laser generation by high temperature (> 100 eV) plasma column excitation in small diameter (4 mm) ceramic capillary, is reported. Radiation at 46.9 nm, produced by a very fast high voltage pulse (∼50 ns, 300 kV) in Neon-like argon, according to a technique initiated by J.J.Rocca et al. [1], has been investigated by multilayer mirrors. Evidence is given for Z-pinch in the plasma column at about 40 kA, with associated X-ray generation. Application of this table-top X-ray source have been considered in different fields as X-ray microscopy and lithography.

Characteristics of populations and gains in neon-like argon (Ar IX)

The characteristics of the populations and gain coefficients in Ne-like Ar have been investigated considering the 37 levels of the 2p6, 2p53s, 2p53p, 2p53d, 2s2p63s, 2s2p63p, and 2s2p63d configurations. It was found that large gains on the 3p 1S0−3s 1P1, 3p 3P2−3s 1P1, and 3p 3D2−3s 3P1 transitions are formed for the density between 1018 and 1019 cm−3. The effect of the opacities of the 2p 1S0−3s 3P1, 2p 1S0−3s 1P1, 2p 1S0−3d 3D1, 2p 1S0−3d 1P1, and 2p 1S0−2s3p 1P1 transitions becomes important for a density higher than 1018 cm−3 and even increases the gain on the 3p 1S0−3s 1P1 transition for the opacity of the 2p 1S0−3s 1P1 transition of up to 2.

Amplified spontaneous emission on the J = 2 → 1, 3p-3s transition of neonlike argon in a capillary discharge

We report the observation of amplified spontaneous emission on the J = 2 → 1, 3p-3s transition (C-line) of neonlike argon at 69.78 nm in capillaries of 6-mm bore. The simple discharge is driven by a small capacitor bank having a capacitance of 0.1 μF. Gain coefficients between G = 0.17 cm −1 and G = 0.25 cm −1 are derived.

Lasing on the 3d-->3p neonlike x-ray laser transitions driven by a self-photo-pumping mechanism.

This paper presents an x-ray laser mechanism that uses radiation trapping of the strongest 3${\mathit{d}}^{1}$${\mathit{P}}_{1}$\ensuremath{\rightarrow}2${\mathit{p}}^{1}$${\mathit{S}}_{0}$ neonlike resonance line in an optically thick plasma to create an intense radiation field that radiatively drives population from the neonlike ground state to the 3${\mathit{d}}^{1}$${\mathit{P}}_{1}$ state, which then lases to the 3${\mathit{p}}^{1}$${\mathit{P}}_{1}$ and 3${\mathit{p}}^{3}$${\mathit{P}}_{1}$ states. Collisional mixing of the 3p states with nearby 3s and 3d states depopulates the lower laser states. Modeling is presented for this mechanism in neonlike argon. Strong gain is predicted on the two 3d\ensuremath{\rightarrow}3p transitions at 451 and 465 \AA{}, the first of which has been observed in recent x-ray laser experiments using an argon gas puff. This pumping mechanism also enhances the population of the 3${\mathit{p}}^{1}$${\mathit{S}}_{0}$ state and the gain of the two 3p\ensuremath{\rightarrow}3s, J=0\ensuremath{\rightarrow}1 transitions, which are at 431 and 469 \AA{} in argon. \textcopyright{} 1996 The American Physical Society.

Demonstration of Soft X-Ray Lasing with Neonlike Argon and Nickel-like Xenon Ions Using a Laser-Irradiated Gas Puff Target

We report the first demonstration of soft x-ray amplification in an elongated plasma column produced by laser irradiation of a gas puff target. The gas puff target is formed by the pulsed injection of gas from a high-pressure solenoid valve through a nozzle in the form of a narrow slit. The plasma column to be used as an x-ray laser active medium is produced by irradiating the gas puff target with a high-power laser beam focused to a line. Lasing in neonlike argon at 46.9 nm and strong indications of lasing in nickel-like xenon at 10.0 nm were observed.

A capillary discharge as a potential x-ray laser driver

This paper describes a combined theoretical and experimental approach to understanding the capillary spark discharge with specific application to use as a soft x-ray or extreme ultraviolet laser source. Atomic physics calculations have identified several potential laser lines in a collisionally pumped neon-like or nickel-like plasma, and magnetohydrodynamic (MHD) modeling has shown that a capillary discharge device should be capable of producing the correct plasma conditions to achieve a population inversion in some of these lines. An experiment is constructed to evaluate the accuracy of the MHD model and investigate the potential of observing inversion in a neon-like argon or a nickel-like krypton plasma.

A Capillary Discharge as a Potential X-Ray Laser Driver

This paper describes a combined theoretical and experimental approach to understanding the capillary spark discharge with specific application to use as a soft x-ray or extreme ultraviolet laser source. Atomic physics calculations have identified several potential laser lines in a collisionally pumped neon-like or nickel-like plasma, and magnetohydrodynamic (MHD) modeling has shown that a capillary discharge device should be capable of producing the correct plasma conditions to achieve a population inversion in some of these lines. An experiment is constructed to evaluate the accuracy of the MHD model and investigate the potential of observing inversion in a neon-like argon or a nickel-like krypton plasma.

Relative intensities of 3p-3s transitions in neonlike Ar IX.

Argon was added in small amounts to [theta]-pinch discharges in hydrogen and deuterium, and the relative intensities of all 3[ital p][r arrow]3[ital s] transitions of neonlike argon were measured at the peak of the Ar IX concentration. At this time recombination was small since the ion was in an ionizing regime; effective excitation of the 3[ital p] levels was essentially due to direct collisional excitation from the ground state and cascading contributions after excitation to higher levels. The relative intensities are compared with theoretical calculations, which employed various collisional and radiative transition rates given in the literature. Very good overall agreement is obtained with a collisional-radiative model which includes all levels up to [ital n]=5.