| Popis: |
Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex eff ect, based on weak attractive fo rces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alterna tive approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi- quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 P m. The observed excited states include the 4 2 F J states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in eac h case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may al so be excitation of other lasing transitions at infrared wavelengths. Keywords: optically pumped atomic lasers, alkali lasers, exciplex, collisional energy pooling |
