Date of Award

3-21-2013

Document Type

Thesis

Degree Name

Master of Science in Applied Physics

Department

Department of Engineering Physics

First Advisor

Glen P. Perram, PhD

Abstract

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.

AFIT Designator

AFIT-ENP-13-M-41

DTIC Accession Number

ADA582423

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