Transverse optical pumping of e-beam excited high-pressure He/Ar mixture with a laser diode array

An opportunity of developing a laser with optical pumping from metastable ArI levels produced by a relativistic electron beam in high-pressure He-Ar gas mixtures was studied. It was shown that high population and long lifetime of the 1s5 level of Ar atom and broad width (~ 10 nm) of the absorption spectral line made it possible to obtain the most optimal lasing conditions in the afterglow of electron beam pulse within the classical three-level pumping scheme. Rate constants for collisional quenching of low-lying 4s-levels of excited argon atom in He-Ar mixtures in the pressure range from 4.0 to 0.75 atm were measured. An increase of photoluminescence on the 2p10-1s5 transition (912.3 nm) upon application of transverse optical pumping with a laser diode array (811.5 nm) was observed. An application of a semi-transparent cavity resulted in a significant increase of this photoluminescence signal in the afterglow indicating amplified spontaneous emission.