High-frequency modulation of Ar-ion laser radiation due to stable two-mode oscillation

Both the spectral and temporal behaviour of argon-ion laser radiation is observed near threshold. It is shown, that in certain ranges of excitation a stable two-mode operation in the argon-ion laser leads to a modulation of the laser radiation at frequencies between 500 MHz and 900 MHz with a very high degree of modulation. Moreover, the first observation of a hysteresis effect is reported.