fotokatoda

Fotokatoda is a term often used in technical contexts, particularly in relation to vacuum tubes and light sensors. It refers to the cathode of an electronic device that is designed to emit electrons when struck by photons, a phenomenon known as the photoelectric effect. In essence, a fotokatoda is a light-sensitive electrode.

These devices are crucial components in many optoelectronic applications. When light of an appropriate wavelength and energy strikes the surface of the fotokatoda, it can impart enough energy to electrons within the material to overcome the material's work function. These energized electrons are then emitted from the surface and can be collected by an anode, generating an electrical current that is proportional to the intensity of the incident light.

Fotokatodas are typically made from materials with low work functions, such as alkali metals (like cesium or potassium) or their alloys, often deposited on a substrate. The specific material choice influences the spectral sensitivity of the fotokatoda, determining the range of light wavelengths it can effectively detect.

Applications for devices incorporating a fotokatoda are widespread. They are found in photomultiplier tubes (PMTs), photodiode detectors, image intensifiers, and various types of light meters. Their ability to convert light signals into electrical signals makes them indispensable for sensing, measurement, and imaging across a broad spectrum of scientific and industrial fields, including astronomy, medical diagnostics, and industrial automation.