The nitrogen ion laser pumped by charge transfer

It is noted that in terms of spectral density, the outpouts from the nitrogen ion laser greatly exceed those from free-running excimer lasers because of the relatively narrow linewidths resulting from the bound-bound transition in N2(+). The laser linewidth at 471 nm is 0.007 nm without any supplementary etalons in the laser cavity and without injection locking of the frequency to a narrow bandwidth. Owing to the combination of visible wavelengths, simultaneously high-output-power densities and efficiencies, narrow linewidth, and freedom from run-away superfluorescence, the nitrogen ion laser holds considerable promise as a practical device. Both theory and the experimental results reported here suggest that the performance of the nitrogen ion laser can approach that of the better excimer laser to within a factor of two or three. It is pointed out that all of the advantages of this type of device that were expected from theory have now been confirmed experimentally.