The science of light's behavior, acting neither as a particle nor a wave
- Microwave photonics - the generation, transmission and manipulation of microwaves
- Photochromism - the reversible transformation of a chemical species between two forms by the absorption of electromagnetic radiation
- Photoluminescence - or PL, a process in which a substance absorbs photons and then re-radiates photons
- Photothermal effects - the production of thermal energy produced by the photoexcitation of materials
- Radiative recombination - the process by which an ion binds an electron to produce a new state with subsequent radiation of photons
- Spontaneous emission - the process by which a light source undergoes a transition to a state with a lower energy and emits a photon
This category has the following 6 subcategories, out of 6 total.