The performance of Xe*2 as a 172-nm fluorescence or laser source when pumped by a low-current, long-pulse electron beam was determined. The fluorescence efficiency of Xe*2 is near the theoretical limit of ∼50% at modest pressures over a range of pump rates up to 106 W/cm. The laser efficiency is limited to values <1% by a very strong medium absorption that is probably due to Xe*2 photoionization. Laser performance is further degraded by early pulse termination that appears related to mirror degradation. An improved kinetics and extraction code was developed to model the performance of the Xe*2 system. A key component of the model is a more detailed treatment of the interactions between secondary electrons and excited atomic and molecular xenon states. Rates for these processes were derived as described herein. With this model, good absolute agreement was obtained between experiments and calculated parameters at pressures as low as 0.5 atm.

The performance of Kr*2 as a 146 nm fluorescence or laser source when pumped by a low-current, long-pulse electron beam has been determined. The fluorescence efficiency of Kr*2 is near the theoretical limit of ∼46% at modest pressures over a range of pump rates up to 3×105 W/cm3. Lasing could not be achieved under the conditions studied here. An improved kinetics and extraction code has been developed to model the performance of the Kr*2 system. A key component of the model is a more detailed treatment of the interactions between secondary electrons and excited atomic and molecular xenon states. Estimated rates for these processes are presented. With this model, good absolute agreement of model predictions with experimental results has been obtained at pressures as low as 0.5 atm.

Eigenmodes characterized by distinct polarization states for the resonator configuration known as the High-Extraction Decentered Annular Ring Resonator (HEXDARR) have been found. The effects of internal annular optical elements (waxicons, reflaxicons, and cones) as well as coatings and mode rotation are included. For a good design, the low-order mode polarization states are nearly circular, with the polarization ellipse orientation and phase angle slightly spatially dependent across the near field of the resonator output. The two lowest-loss eigenmodes are separated by only a small loss which is dependent on the coating properties, one being principally right-hand circularly polarized and the other principally left-hand circularly polarized.

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