Xenon excited‐state densities in electron‐beam pumped XeCl and XeF

Kannari, F.; Kimura, W. D.; Seamans, J. F.; Guyer, Dean R.

doi:doi:10.1063/1.341989

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Low‐energy electron distribution in electron‐beam‐excited XeCl laser mixtures

The electron energy distributions for energies lower than 17 eV and their time‐dependent evolution are calculated for electron‐beam‐excited Ne/Xe/HCl mixtures. A time‐dependent Boltzmann equation including all interactions between electrons and ground– or excited‐state species is solved together with a detailed full kinetics model for XeCl lasers. The effects of electron‐electron collision, HCl concentration, and excitation rate on the steady‐state electron energy distribution are examined. Unde...

Lasing characteristics of Er³⁺‐doped silica fibers from 1553 up to 1603 nm

The laser oscillations from 1553 up to 1603 nm have been demonstrated in Er3+‐doped silica fibers with a doping rate of 2500 ppm. Wide changes in laser oscillation wavelengths are due to broad splitting of the upper sublevels in the 4I15/2 manifold, caused by the random structure of the silica matrix. It has been shown that unpumped parts of the Er3+ ions in the end pumped fiber laser configuration play an important role in the wavelength changes of the laser oscillation. For an absorbed pump po...

Understanding of the neutral channel formation kinetics in excimer laser gas mixtures has been limited by the lack of data on the pertinent excited‐state populations in these mixtures. Presented are time‐dependent measurements of the lower level xenon excited‐state densities in electron‐beam (e‐beam) pumped XeCl and XeF laser mixtures (neon diluent). Measurements are obtained using hook interferometry under nonlasing conditions at an average excitation rate of ≊250 kW/cm³ and e‐beam pulse lengths of 0.4 and 1 μs. The population differences, ΔN∗, between four different electronic transitions [three in the Xe∗(6s)‐Xe∗∗(6p) manifold, and one in the Xe∗∗(6s′)‐Xe∗∗∗(6p′) manifold] are examined as a function of halogen concentration. For both XeCl and XeF at high initial halogen concentrations (>4 Torr), the ΔN∗ densities of the Xe∗(6s) and Xe∗∗(6s′) transitions are relatively constant during the 0.4‐μs e‐beam pulse [for ΔN∗(6s‐6p): ≊4×10¹⁴ cm⁻³ for XeCl, and ≊1.5×10¹⁴ cm⁻³ for XeF]. At lower initial halogen concentrations, the ΔN∗ densities of 6s‐6p and 6s′‐6p′ start at the beginning of the pulse at approximately the same densities as the richer halogen mixtures, but at a certain point during the pulse, the ΔN∗ densities abruptly increase. This increase can be >10 times for very lean halogen mixtures (1–2 Torr), and occurs at earlier times as the initial halogen concentration is reduced. From other measurements, this increase appears related to the depletion of the halogen. The observed lifetime of the Xe∗(6s) densities is ≊2 μs for the low initital halogen concentration mixtures. Additional density data for halogen‐free Ne/Xe and Ar/Xe mixtures are also presented.