A sensor for detecting and localizing laser beam sources, includes a beam-sensitive detector which is arranged in the image field of an imaging optic, an electric image processing device which is connected to the detector, and an optical diffraction element which is arranged in the beam path. The diffraction properties of the optical diffraction element are such that incident laser light on different wavelength bands produce diffraction patterns with different shapes, and the electronic image processing device is designed such that it can detect and evaluate the different forms of the diffraction pattern.