How do photoelectric detectors help create images in night-vision devices?

Photoelectric detectors are fundamental to the operation of night-vision devices, which rely on the photoelectric effect to convert low-level light into a visible image.12

In these devices, incoming light—such as moonlight or starlight—strikes a photocathode, causing the emission of electrons. This process creates an "electron current" image that corresponds to the spatial distribution of the original light. To make this faint signal visible, the device typically employs a microchannel plate multiplier, which amplifies the electron flow by triggering a cascade of secondary electrons.12

These amplified electrons are then directed onto a phosphor screen. When the electrons strike the screen, they cause the phosphor to glow, producing a bright, intensified version of the original scene that can be viewed directly or captured by an imaging tube. By utilizing materials sensitive to infrared light, such as lead sulfide or mercury cadmium telluride, these sensors can effectively detect targets even in near-total darkness.123