| The photocathode in the night scope that converts visible light into electrons is sensitive to both visible light and some infrared radiation. |
| Traditional night-vision scopes use image intensifiers and photocathode tubes to convert light into electrons, which are projected on a phosphor screen for viewing. |
| Optocoupler consists of LEDs on one side and a photodiode, phototransistor, or triac photocathode on the other side. |
| A catadioptric lens sucks ambient light from near darkness and funnels it to an image-intensifier-tube photocathode. |
| The optical train uses two aspherical lenses to collimate and focus the light on the PMT photocathode. |
| The photocathode recombines the protons and electrons to form hydrogen gas. |
