A laser active optronic system has an emission channel for the emission by an emission source of a laser beam which illuminates a target, and a receiving channel for receiving the wave backscattered by the target. An optical switching device is positioned in the receiving channel to receive the backscattered wave and has an optical gain medium and pumping means for pumping the gain medium. The gain medium is absorbent at the wavelength of the laser and becomes substantially transparent when it is pumped to allow the switching device to be actuated in the on mode or off mode respectively. A control unit for controlling the pumping means, allows the switching device to be actuated in the on mode in at least one temporal window of predetermined duration, triggered at a predetermined instant after the start of emission of the illuminating laser beam.