Numerical studies of the CO2 waveguide laser: application of a numerical model to explain experimental results and conclusions for laser efficiency and lifetime

Abstract

Some effects of CO2 lasers are studied using a numerical model. A small amount of water vapour increases the output power only in the case of nitrogen-rich gas mixtures due to reduction of CO2 dissociation, but a better way is the use of a higher CO2:N2 ratio. In typical waveguide laser gas mixtures, the degree of dissociation has only a small influence on output power, if it is below 70-80%. That is why catalysts cannot increase the laser output power; they are only useful for a longer laser lifetime. Using a zeolitic stabilization method for the CO2 partial pressure, laser lifetimes up to 60000 h can be achieved. A method of studying the behaviour of the gas discharge of long traversely radiofrequency-excited waveguide lasers on the basis of the numerical model is presented. A further method is developed for determination of the time-averaged reduced effective field strength in such lasers.