Transition from laser-off to laser-on through on–off intermittency in a gain-modulated CO_2 laser

We observe the route from laser-off to laser-on in a CO2 laser. On the route, on–off intermittency appears, which is caused by discharge instability near the laser threshold. By analyzing the probability distribution of a laminar phase near the onset of the intermittency, we confirm that what we have observed is on–off intermittency. We reproduce the intermittency through a numerical simulation of the laser rate equations.