Scaling of an Optically Pumped Mid-Infrared Rubidium Laser

Author

Paul J. Moran

Date of Award

3-26-2015

Document Type

Thesis

Degree Name

Master of Science in Applied Physics

Department

Department of Engineering Physics

First Advisor

Glen P. Perram, PhD.

Abstract

An optically pumped mid-infrared rubidium (Rb) pulsed laser has been demonstrated in a heat pipe along the 6²P_3/2 - 6²S_1/2 transition at 2.730 µm and the 6²P_1/2 - 6²S_1/2 transition at 2.790 µm. The bleached limit, slope efficiency, and maximum laser output energy of the mid-IR Rb laser have been shown to scale linearly with increasing Rb density, contrary to prior laser demonstrations. A maximum output energy of 5 nJ per pulse had previously been observed before a rollover occurred in the scaling of output energy with Rb concentration. In this experiment, the maximum laser output energy observed was 100 nJ, with linear scaling to a Rb concentration of 7 x 10¹⁵ cm^-3. A maximum slope efficiency of 1.7 x 10⁴ was observed. Evidence that only a small percentage (2%) of the available pump photons were absorbed at a concentration of 2 x 10¹⁵ cm^-3 and a pump energy of 10 µJ. This indicated that there were ~20,000 pump photons per Rb atom at a pump energy of 10 mJ, and that the effective laser efficiency was 0.65% or higher. The hyperfine structure and absorption spectral profile of the 52S_1/2 - 6²P_1/2 and 5²S_1/2 - 6²P_3/2 (blue) pump transitions were studied using a continuous wave (cw) pump source.

AFIT Designator

AFIT-ENP-MS-15-M-104

DTIC Accession Number

ADA614929

Recommended Citation

Moran, Paul J., "Scaling of an Optically Pumped Mid-Infrared Rubidium Laser" (2015). Theses and Dissertations. 88.
https://scholar.afit.edu/etd/88