fotokatoddan

A fotokatoddan, often translated as photocathode, is a component within a vacuum tube or photodetector that emits electrons when struck by photons. This phenomenon is known as the photoelectric effect. The photocathode is typically a thin layer of a photosensitive material, such as a metal or a semiconductor, coated onto a transparent substrate. When light of sufficient energy (photons) interacts with the photocathode's surface, it can excite electrons within the material. If these electrons gain enough energy, they can overcome the work function of the material and be emitted into the vacuum space. The number of emitted electrons is proportional to the intensity of the incident light and the quantum efficiency of the photocathode material at that particular wavelength. Different photocathode materials are sensitive to different ranges of the electromagnetic spectrum, from ultraviolet to visible and even infrared light. Fotokatoddans are crucial components in devices like photomultiplier tubes, image intensifier tubes, and certain types of photodetectors used in scientific instruments and imaging applications. Their sensitivity and spectral response are key factors determining the performance of these devices.