Electron beam pumped tunable excimer lasers

Laser characteristics of the broadband rare gas halide Xe2Ce, Kr2F, and XeF (C yields A) were investigated. Since all three excimers have unbound ground states, a spectrally wide emission bandwidth is available for wavelength tuning. Other excimers with wide band fluorescence emissions were studied but had gains too small to achieve laser threshold in a 10 cm transversely pumped laser cavity. Mixture optimization, variation of optical resonator configuration, and influence of different halogen donors and buffer gases were studied. Tuning was accomplished by using cavity mirrors with different center wavelengths. The trimer Xe2Cp had a nominal peak wavelength of 518 nm. Laser pulse widths were about 36 nsec, and were delayed by 35 nsec from the e-beam excitation current pulse. This delay was observed in the other lasers as well, and can be attributed to transient absorption by molecular argon. Atomic absorptions by xenon metastables to Rydberg levels were identified in the laser spectrum. The kinetics of Xe2Cl were also studied. The triatomic excimer Kr2F lased at 436 nm. The pulse duration was approximately XeF(C yields A) had the largest laser output intensity. The peak wavelength was 486 nm, with tuning range f 30 nm. Pulse duration was approximately 30 nsec. Xenon absorption lines were identified which belonged to the same series as observed for the Xe2Cl laser.