Fotokathode

The fotokathode, also known as the photocathode, is a type of cathode that is sensitive to light. It is a component of photomultiplier tubes and image intensifiers, and is used to convert light into electrical signals.

The fotokathode is typically a thin layer of material that is deposited on a substrate. The most common materials used for the fabrication of fotokathodes are metals such as cesium, antimony, and palladium. The layer is only a few micrometers thick and is designed to absorb light efficiently.

When light hits the fotokathode, it transfers its energy to the electrons in the material, causing them to be emitted and flow towards the anode. This process is known as the photoelectric effect. The resulting flow of electrons is amplified by the photomultiplier tube, producing a significant increase in the signal strength.

One of the key characteristics of the fotokathode is its ability to produce a high sensitivity to low levels of light. This makes it an essential component in many applications, including night vision devices, radiation detection systems, and scientific instruments. However, the fotokathode has some limitations, such as a relatively short lifespan and sensitivity to environmental factors.

The fotokathode was first discovered in the early 20th century and has since become a crucial element in many optical and electrical devices. Despite its limitations, it remains a widely used component in many applications due to its high sensitivity and ability to convert light into electrical signals.