We study the dynamics of an electrically pumpedp‐Ge laser with frequency fixed to 100 cm−1by a novel selective cavity. The growing laser power increases the pump current long before it reaches a saturating power level, an effect explained by photoionization. We further find that the laser pulse can be delayed or even quenched by injected off‐resonance far‐infrared radiation. This effect not only gives a gain coefficient of 0.01 cm−1and a saturation power of 400 W−which confirms the high‐power capability of the laser−but furthermore reveals a novel quasihomogeneous broadening of the gain spectrum caused by transit‐time effects of rapidly moving holes.