Digital image overlay in image intensified and telescopic system

An optical system for overlaying a first image of a scene and a second image, comprising:

• a first imaging device providing the first image, the first imaging device comprising an analogue optical device selected from the group consisting of an image intensified night vision device, and telescopic optics;
• a second imaging device comprising an image display and collimation optics providing the second image;
• and
• a waveguide, optically downstream from the image display, comprising:
• a first diffraction grating configured to receive the first image;
• a second diffraction grating configured to receive the second image;
• and
• a guide portion disposed between the first diffraction grating and the second diffraction grating configured to convey the second image to the first grating,
• wherein the first diffraction grating is configured to overlay the first image and the second image.