Optical gain and excitation phenomena in optically pumped alkali atom-rare gas mixtures

Galbally-Kinney, Kristin L.; Maser, Dan L.; Kessler, William J.; Rawlins, W. T.; Davis, Steven J.

doi:10.1117/12.912863

Cited by 2 publications

(1 citation statement)

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“…The observed gain values are comparable to small-signal gains observed for DPAL configurations in similar bench-scale systems. 14, 15 We observed stable, CW laser oscillation on the Ar(2p 10 →1s 5 ) transition at 912.3 nm, with high optical efficiency (~55%). These results demonstrate that microwave micro-discharge arrays are viable media for development of CW optically-pumped rare-gas metastable laser systems.…”

Section: Summary: Initial Ar* Investigationsmentioning

confidence: 92%

Laser excitation dynamics of argon metastables generated in atmospheric pressure flows by microwave frequency microplasma arrays

et al. 2014

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The optically pumped rare-gas metastable laser is a chemically inert analogue to diode-pumped alkali (DPAL) and alkali-exciplex (XPAL) laser systems. Scaling of these devices requires efficient generation of electronically excited metastable atoms in a continuous-wave electric discharge in flowing gas mixtures at atmospheric pressure. This paper describes initial investigations of the use of linear microwave micro-discharge arrays to generate metastable rare-gas atoms at atmospheric pressure in optical pump-and-probe experiments for laser development. Power requirements to ignite and sustain the plasma at 1 atm are low, <30 W. We report on the laser excitation dynamics of argon metastables, Ar (4s, 1s 5 ) (Paschen notation), generated in flowing mixtures of Ar and He at 1 atm. Tunable diode laser absorption measurements indicate Ar(1s 5 ) concentrations near 3 x 10 12 cm -3 at 1 atm. The metastables are optically pumped by absorption of a focused beam from a continuous-wave Ti:S laser, and spectrally selected fluorescence is observed with an InGaAs camera and an InGaAs array spectrometer. We observe the optical excitation of the 1s 5 →2p 9 transition at 811.5 nm and the corresponding laser-induced fluorescence on the 2p 10 →1s 5 transition at 912.3 nm; the 2p 10 state is efficiently populated by collisional energy transfer from 2p 9 . Using tunable diode laser absorption/gain spectroscopy, we observe small-signal gains of ~1 cm -1 over a 1.9 cm path. We also observe stable, continuous-wave laser oscillation at 912.3 nm, with preliminary optical efficiency ~55%. These results are consistent with efficient collisional coupling within the Ar(4s) manifold.

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Section: Summary: Initial Ar* Investigationsmentioning

confidence: 92%