The atomic xenon laser operates on seven infrared transitions (1.73–3.51 μm) between the 5d and 6p manifolds. Intrinsic laser power efficiencies exceeding 5% have been previously obtained in Ar/Xe mixtures, principally at 1.73 μm (5d[3/2]1→6p[5/2]2). The kinetic mechanisms responsible for this performance, though, are not well understood. In this paper, we report on a computer model for the electron-beam-pumped xenon laser in Ar/Xe mixtures with which we have investigated some of these excitation mechanisms. Based on the results of a parametric study of power deposition (50 W cm−3 to 100 kW cm−3), gas pressure (0.5–6 atm), and xenon fraction, we suggest that the high efficiency obtained in Ar/Xe mixtures is due to rapid collisional cascade to the upper laser level of the 1.73-μm transition following dissociative recombination of ArXe+ and selective quenching of the lower laser level of the 1.73-μm transition by collisions with argon. The results of our model indicate that the decrease in laser performance at high Xe fractions results from electron-impact excitation of the lower laser levels (6s→6p) and quenching of the 5d manifold by collisions with atomic xenon. The degradation of laser performance at high specific power deposition is most likely due to electron-collision mixing of the 5d and 6p manifolds. As a result of the lower levels being cleared dominantly by atomic collisions, we predict that optimum performance is then obtained at higher gas pressures when increasing power deposition. The results of the model predict that optimum power deposition is obtained when the fractional ionization is ≊2–3×10−6.

We investigated theoretically the efficiency enhancement of discharge-pumped vacuum-ultraviolet F2 lasers using He/F2 mixtures in terms of the laser kinetics. As a result, the high mixture pressure is found to be essential for the high-efficiency operation. Intrinsic efficiency in excess of 1% may be obtainable. Using a 6-atm mixture of He/F2=98.5/0.15%, intrinsic efficiency of 1.5% may be obtainable with a specific output energy of 2.6 J/l.

The effect of buffer gases on the operating performance of a self-sustained discharge ArF laser employing a charge transfer excitation circuit has been analyzed theoretically. By the analysis of the electron kinetics, the ArF* formation, the ArF* relaxation, and the absorption of the B→X laser radiation, the pump rate dependence of intrinsic efficiency, small-signal gain, and absorption could be clarified for the Ne- and He-diluted mixtures. It is found that there is no appreciable difference in the intrinsic efficiency of the ArF laser between Ne- and He-diluted mixtures when employing a laser resonator with a strong output coupling. After optimizing output coupling in each case, a higher efficiency is obtainable for the Ne diluent than for the He diluent. For a 4-atm mixture of 4.9% Ar and 0.1% F2 in Ne, an intrinsic efficiency of 4% is obtainable, while less than 2% is obtainable for the He-diluted mixtures. However, a higher specific output energy is achievable for the He-diluted mixtures than the Ne-diluted mixtures because the use of He-diluted mixtures can efficiently transfer the stored energy to the laser discharge load.

The atomic xenon (5d + 6 p) infrared laser has been experimentally and theoretically investigated using a short pulse (30 ns) high power (1-10 MW/cm3) coaxial electron beam excitation source. In most cases, laser oscillation is not observed during the e-beam current pulse. Laser pulses of 100's of ns duration are subsequently obtained, however, with oscillation beginning 60-800 ns after the current pulse terminates. Results from a computer model for the xenon laser reproduce the experimental values, and show that oscillation begins when the fractional electron density decays below a critical value of = 0.2-0.8 x lo6. These results lend credance to the proposal that electron collision mixing of the laser levels limits the maximum value of specific power deposition which may be used to efficiently excite the atomic xenon laser on a quasi-CW basis. Manuscript received May 2, 1990. The work of P. J. Peters and Y. F. Lan is part of the research program of the "Stichting voor Fundamenteel Onderzoek der Materie (FOM)," which is supported by the "Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO)". The work of M. Ohwa and M. J. Kushner was supported by Sandia National Laboratory.