Abstract: A laser for generating pulsed laser radiation is provided, having a resonator, a laser-active medium, which is situated in the resonator, a Q-switch, which is situated in the resonator, and which can be put into a first state and a second state to set the resonator quality. The resonator quality is lower in the first state than in the second state. The laser also may have a detection unit, which, when the Q-switch is in the second state, measures the intensity of the building laser pulse and outputs it as an intensity signal. The laser may further have a control unit for controlling the Q-switch, which, as a function of a predetermined pulse duration and the applied intensity signal, switches the Q-switch from the second state into the first state, before the pulse buildup of the laser pulse is completed.