If I have a laser cavity with a bunch of harmonics under the gain curve:
I mean since these harmonics exist in the cavity arn't they always in phase because the ends are closed and they create standing waves in phase to each other? Where does the out of phase aspect come from ? Mirror imperfections -> implying the length of the cavity is not constant? I mean I am wondering, why not all lasers are pulsed, since there is always going to be more than one frequency under the gain curve to some degree.