Imaging system with optical filter for scattered laser radiation

An imaging system is provided for viewing a target. The imaging system includes a first diffraction grating receiving collimated infrared light containing infrared (IR) object light generated by the target and IR laser light produced when the laser beam contacts the target. The diffraction grating disperses the object and laser light. A first lens is aligned with the diffraction grating to focus each wavelength at a separate focal point. A mask is disposed at the focal plane of the first lens. The mask is divided into a plurality of segments, each of which is uniquely associated with a spectral line of a wavelength of object or laser light. The mask segments include either a blocking region or an aperture. Each blocking region is located at a spectral line of laser light. The apertures extend between the blocking regions. The mask blocks the laser light and passes the object light. A second lens is aligned to receive and focus the object light passed through the mask onto an image plane. A second diffraction grating is positioned at the image plane of the second lens. The second diffraction grating recombines the object light into a single output image with the laser light removed therefrom.