Yu B Konev

Theoretical modelling and experimental studies of the multi-quantum vibration exchange in vibrationally excited CO molecules

Studies of the vibration-vibration (VV) exchange in CO molecules excited up to vibration quantum numbers v = 20 have been performed both theoretically and experimentally. A new kinetic model which takes into account the multi-quantum VV exchange in the temperature range T = 100-300 K is described for the first time. A description is given of the experimental methodology allowing for studies of the effects of the relaxation of the vibrational distribution after a sudden disturbance. The disturbance of the vibrational distribution is produced by a Q-switched short pulse of single line radiation in fundamental band. The relaxation is studied by measuring the laser pulse energy of the second pulse initiated by resonator Q-switching produced with a variable time delay relative to the first pulse. A set of kinetic rate constants accepted in the model for various gas temperatures, vibration level numbers and number of exchanged vibration quanta from 1 to 4 is presented. The good agreement between the experimental data and the results of the advanced theory is the first direct evidence in support of the multi-quantum exchange model.

Characteristics of unstable resonators with field distortions in their components. II. Spherical mirrors

The fast Fourier transformation method is used to obtain a numerical solution of the integral equations describing an unstable confocal resonator with spherical mirrors. A study is made of the field distortions characteristic of the operation of a resonator filled with a fast-flowing active medium, such as asymmetric distortions of the mirror surfaces simulating thermal deformation, small-scale random phase inhomogeneities, and a phase inhomogeneity resulting from the formation of compression and expansion waves in a supersonic stream. Calculations are made of the situation in the case of lasing in a fast-flowing stream consisting of a mixture of carbon dioxide, nitrogen, and water vapor.