Relaxation oscillations in optically pumped molecular lasers

We report the observation of relaxation oscillations in both the C
¹³
H
3
F and C
¹²
H
3
F optically pumped lasers. Expressions are derived for the oscillation frequency and its temperature and pressure dependences using a four-level rate equation model. We observe excellent agreement between measured frequencies and the theory presented. Models are considered for using this phenomenon to determine the rotational and vibrational relaxation mechanisms of the laser gases.