Anharmonic oscillator lasers

Emphasis of the work performed under this contract has been placed on fundamental theoretical and experimental studies of various phenomena associated with diatomic molecular gas flows in which anharmonicity plays an important role in producing or maintaining an inversion which is suitable for lasing. Most of the work concerned carbon monoxide gas dynamic or electrically excited flows because these systems were capable of being studied in our laboratories, had considerable potential practical importance, and displayed many characteristics common to other diatomic gas lasers. In several cases the results may be generalized to other systems. Study of the master kinetic equations demonstrated that approximate analytical solutions exist under certain conditions. It is shown that quantitative prediction of the vibrational population distribution can be determined from knowledge of just a few key parameters in many cases of practical interest. The experimental measurement of small signal gains in highly expanded CO-N2 mixtures confirmed the anticipated large gains achievable at very low temperatures. However, unexpected rotational nonequilibrium was observed which can limit the power available from P branch laser lines. A summary of efforts to provide a simplified method of computing vibrational excitation rates in a discharge is presented. A modified E/N parameter was established which is shown to correlate results determined in a variety of gas mixtures. An experimental study of a double discharge excitation scheme in a supersonic CO-N2 flow disclosed that the secondary pin discharge is not capable of providing a stable discharge with independently controlled E/N under the conditions tested.