Phase conjugation at intracavity degenerate four-wave mixing of frequency-selective pulsed CO laser radiation

Abstract

Energetic, temporal and spectral characteristics of the process of phase conjugation (PC) at intracavity degenerate four wave mixing (DFWM) of frequency selective pulsed e-beam controlled discharge CO laser radiation have been studied both experimentally and theoretically. Maximum PC reflectivity (PCR) on energy comes up to 1.5% being independent of specific input energy. The dependencies of PCR on energy have quite different behavior for various selected spectral lines. An influence of lasing and PC process in adjacent vibrational bands on PCR for the selected spectral line has been experimentally demonstrated, PCR decreasing at switching on adjacent vibrational bands. The numerical model has been formulated to simulate the temporal behavior of PC process on large scale gain (amplitude) and refraction (phase) gratings formed in the active medium of CO laser. The trend in the calculated temporal behavior of PCR is the same as for the experimental result, the theoretical PCR being higher as compared to experimental one. The resonance (amplitude) mechanism of PC process seems to be a prevailing one for DFWM of CO laser radiation.