Transient behaviors of output power in fast-axial flow-type CO laser

Transient behaviors of output power were experimentally investigated with the parameters of discharge current I-dis, discharge length l, gas-flow velocity v, and O-2 concentration for a compact dc discharged fast-axial how (FAF) CO laser, and were theoretically explained, together with some empirical equations. Introducing the discharge time (t) dependence into the gas temperature and the concentration of O-2 and CO2 molecules, based on the experimental data and the mass-spectrum analysis, respectively, the overall population density of CO molecule n(v') toward an arbitrary vibrational level has been expressed as a function of t. Then, since the gain parameter can also be given as a function of t, together with the measured laser parameters such as the saturation intensity I-s, a measure of partial homogeneity m, and the Voigt function psi, the transient behaviors of the output power as a function of t were well explained, being in good agreement with the experimental results and the calculations. From these analyses, it was found that control of the gas temperature rise and suppression of both the decrease of O-2 and the increase of CO2 concentrations are required to relax this unnecessary power reduction due to the transient behaviors.