Date of Award


Document Type


Degree Name

Master of Science


Department of Engineering Physics

First Advisor

Glen P. Perram, PhD.


Mirrorless lasing has been successfully demonstrated in a Rubidium heat pipe. Lasing was observed on the 62P3/2-62S1/2 energy transition at 2.73 µm and on the 62P1/2-62S1/2 transition at 2.79 µm. The transitions were optically pumped from 52S1/2-62P3/2 at 420.2 nm and from 52S1/2-62P1/2 at 421.7 nm, respectively. The 52S1/2-62P3/2 transition was excited over a 36 GHz band, while the 52S1/2-62P1/2 transition was excited over a 24 GHz band. Both pump transitions showed a high degree of saturation and only a small fraction (<1%) of the incident pump energy was absorbed. Output energies of up to 5 nJ were obtained at 2.73 µm and of up to 5.4 nJ at 2.79 µm when pumped at pulse energies of ~4 mJ. Both transitions experienced bleaching at this ~4 mJ pump energy, limiting further IR output energy. Increasing rubidium concentration at bleached pump energies showed no increase in laser energy after ~170 °C, likely due to second order processes. Slope efficiency for both transitions, however, increased linearly with rubidium concentration up to 11 x 10-6. The addition of small amounts of argon, helium, and ethane (5-45 Torr) were found to fully quench lasing action on both transitions.

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