Computer Simulation of cw HF Chemical Laser Unstable Resonator Performance

摘要

Inadequacies in the treatment of the fluid dynamic mixing that were not apparent in Fabry-Perot or stable resonator models were revealed with a wave optics unstable resonator model. The unstable resonator data as a function of resonator size and size of the laser were shown to provide a severe test of a couples, wave optics, chemical kinetic, fluid dynamic model of a chemical laser. A mechanism for the observed time-dependent oscillations that occur on lines whose saturated gain does not fill the unstable resonator was proposed. According to the proposed mechanism, the time-dependent oscillations are the result of a competition between chemical pumping and radiative deactivation of upper laser levels of HF. The oscillations occur only if the media is not strongly coupled to the optical fields diffractively or geometrically. Computer calculations supported the proposed mechanism and new unstable resonator experiments were suggested.