Date of Award

3-10-2010

Document Type

Thesis

Degree Name

Master of Science in Applied Physics

Department

Department of Engineering Physics

First Advisor

Jeremy C. Holtgrave, PhD.

Abstract

This paper develops a three level model for a continuous wave diode pumped alkali laser by creating rate equations based on a three level system. The three level system consists of an alkali metal vapor, typically Rb or Cs, pumped by a diode from the 2S1/2 state to the 2P3/2 , a collisional relaxation from 2P3/2 to 2P1/ 2 , and then lasing from 2P1/2 to 2S1/2 . The hyperfine absorption and emission cross sections for these transitions are developed in detail. Differential equations for intra-gain pump attenuation and intra- gain laser growth are developed in the fashion done by Rigrod. Using Mathematica 7.0, these differential equations are solved numerically and a diode pumped alkali laser system is simulated. The solutions of the differential equations are then utilized to characterize the inversion, the gain profile, the output laser intensity, and the pump intensity absorption profile for many different diode pumped alkali laser systems. The results of the simulation are compared to previous experimental results and to previous computational results for similar systems. The absorption profile for the three level numerical model is shown to have excellent agreement with previous absorption models. The lineshapes of the three level numerical model are found to be nearly identical to previous developments excepting those models assumptions. The three level numerical model provides results closer to experimental results than previous systems and provides results which observe effects not previously modeled, such as the effects of lasing on pump attenuation.

AFIT Designator

AFIT-GAP-ENP-10-M06

DTIC Accession Number

ADA516382

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