Theory Study Of TEA-CO₂Laser Injection-locking

Injection locking techniques exist in many laser applications, such as nonlinear optics,laser radar, and excimer laser in optical lithography. In this paper, theoretical studies oninjection locking of TEA （Transversely Excited Atmospheric） CO₂laser based on sixtemperature model are reported, in which mainly the following works are included:First, the six temperature model of TEA-CO₂laser was described, based on which andthe classical four-order Runge-Kutta algorithm the common results were reproduced. It isfound in the studies that the laser pulse waveform can match better with the experimentalresults in literature after an alignment of the related relaxation rate.Second, optical-field model of injection locking was clarified, and the rate-equationmodel of injection locking was derived from this optical-field model exactly. Based on thisrate-equation model and the six temperature model, the numerical codes for the simulation ofthe injection locking of TEA-CO₂laser with a continuous seed and a pulse seed wereconstructed respectively. It is shown in the numerical results that when a continuous seed isinjected, the occurring time of pulsed laser becomes earlier, the width becomes broader, andthe peak power becomes lower; when a pulsed seed is injected, there is a time window forbest performance, which explained the unstable phenomena found in the experimentalresults.Third, numerical code based on the optical-field model of laser radiation and the sixtemperature model for active particles of the injection locking of TEA CO₂laser isestablished. The spontaneous emission zone, injected locking zone and frequency lockingzone can be found in the numerical results clearly. And it is also found that there is noessential difference in the frequency evolution of the injected radiation between thespontaneous emission zone and injection locking zone under certain conditions, which isinevitable in the framework of classic optical field injection locking theory. At last, theinfluences of the intensity and the detuning angle of the injected optical field intensity were simulated and discussed.