Lasing electron beam pumping

The first lasing of a rare gas-halide (RGH) excimer (XeBr) was reported by Searles and Hart in 1975. Shortly thereafter, lasing from XeF was reported by Brau and Ewing. Both XeBr and XeF lasers were pumped by intense electron beams. Excimers shown in Table I were reported to lase. In addition to electron-beam pumping, researchers have also employed volume-uniform avalanche discharges with X-ray, UV, or corona preionizations, electron-beam controlled discharges, and proton beams successfully to pump a variety of excimer lasers. 

In addition to the triatomic RGHs, a new broad band emission from a fouratomic RGH excimer, ArsF at (430 zb 50) nm was reported by Sauerbrey et al in 1986. A fouratomic ArsF RGH excimer emission (not lasing) was detected from electron-beam pumped Ar/F2 and Ar/NFs mixtures. 

Various broadband sources employed to optically pump Ha include tungsten, mercury, xenon, and krypton lamps. The last source provides an especially good spectral match to the near-infrared absorption bands of Nd3+ in YAG. To reduce lattice heating resulting from the multiphonon emission decay to the F3/2 state, semiconductor diodes and laser sources at 0.8-0.9 ym nave pumped Nd lasers (58). Sun-pumped Nd and chromium-sensitized Nd lasers have been demonstrated and considered for space applications (59). Lasing of Nd3+ by electron beam excitation has also been reported (bO). 

Even though n- and later on p-type doping have been reported in ZnO thin films [ 137], there is no demonstration of electrically pumped lasing in ZnO-based structures. However, optically pumped stimulated emission (SE) has been observed by many researchers from ZnO epitaxial layers grown by a variety of methods [138-141]. There have also been earlier demonstrations, dating back to 1966, of SE and lasing in vapor-grown ZnO platelets, which were cleaved parallel to the oaxis and pumped by an electron beam [142-144]. 

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