Editing Photonics (section)

===Light sources===
Photonics commonly uses semiconductor-based light sources, such as [[light-emitting diode]]s (LEDs), [[superluminescent diode]]s, and lasers. Other light sources include [[single photon sources]], [[fluorescent lamp]]s, [[cathode-ray tube]]s (CRTs), and [[plasma screen]]s. Note that while CRTs, plasma screens, and [[organic light-emitting diode]] displays generate their own light, [[liquid crystal display]]s (LCDs) like [[TFT screen]]s require a [[backlight]] of either [[cold cathode fluorescent lamp]]s or, more often today, LEDs.

Characteristic for research on semiconductor light sources is the frequent use of [[III-V semiconductor]]s instead of the classical semiconductors like [[silicon]] and [[germanium]]. This is due to the special properties of [[III-V semiconductor]]s that allow for the implementation of [[light source|light emitting device]]s. Examples for material systems used are [[gallium arsenide]] (GaAs) and [[aluminium gallium arsenide]] (AlGaAs) or other [[compound semiconductor]]s. They are also used in conjunction with silicon to produce [[hybrid silicon laser]]s.