How does Night Vision work?

Sightmark Night Vision products collect and amplify existing light through the objective lens, which is then focused on the image intensifier. Inside the intensifier, a photocathode is "excited" by the light and converts the photon energy into electrons. These electrons accelerate across an electrostatic field inside the intensifier and strike a phosphor screen, which is similar to a green monochrome TV screen. The phosphor screen then emits an image that you can see. It is the acceleration of electrons, which provides gain and enhances the image.