A COMPUTER MODEL FOR THE DETERMINATION OF FOUR-LEVEL LASER EFFICIENCY
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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Four-level Laser efficiency is maximized by a mathematical model which is developed by identifying the loss mechanisms which operate in the four- level Laser system, defining the system efficiency as the product of six sub- efficiencies, one associated with each loss mechanism, and deriving equations for the sub-efficiencies in terms of physically measurable parameters of the Laser system. The model is limited in its present form to the representation of pulsed four-level Lasers employing helical or annular lamp pumping, but could be easily extended to cover other pumping geometries and continuous operation. Based on the mathematical model, a program is written for the IBM 1620 digital computer which calculates the efficiency of a pulsed four-level Laser oscillator or the maximum efficiency and maximum gain of a pulsed four-level Laser amplifier. The program is written in a modification of IBM FORTRAN. On the basis of the model and the experience gained in its development and testing, it can be concluded that the efficiency of pulsed four-level Lasers will tend to increase as length, radius, doping density, and pumping energy are increased, and decrease as end reflectivities and pumping pulse time constant are increased, within the limits imposed by the assumptions and approximations used in the development of the model.
- Lasers and Masers