Excitation mechanism of the Cd(II) 441.6 nm laser in the positive column He-Cd discharge

The population densities of the upper and lower states of the Cd(II) 441.6 nm laser line in the positive column He-Cd discharge were determined experimentally with the modified absorption method and gain measurements. It has been shown that the influence of the population density of the laser lower state on the laser output power is very large and cannot be neglected in interpreting the saturation of the laser output power. Moreover, it has been concluded that the stepwise excitation process from the Cd(II) ground state is dominant to the laser upper state as well as the Penning excitation process, and is the most dominant to the laser lower state.