Light Emission refers to the process by which light (electromagnetic radiation) is produced and emitted by a source. This can occur through various mechanisms, depending on the nature of the source and the conditions involved. These processes involve the transformation of energy into light.
Luminescence
Light is produced when excited electrons within a material drop back to a lower energy state, releasing energy in the form of light. This category includes:
- Photoluminescence (excitation by light absorption)
- Electroluminescence (excitation by an electrical current)
- Chemiluminescence (excitation by a chemical reaction)
- Bioelectroluminescence (excitation through biological processes in living organisms)
- Thermoluminescence (excitation by heat)
- Sonoluminescence (excitation by sound waves and collapsing bubbles)
- Triboluminescence (excitation by mechanical stress)
Thermal Radiation
- Light is produced due to the thermal motion of atoms and molecules. Any object above absolute zero emits thermal radiation, including a portion in the visible light spectrum.
Nuclear Reactions
- Light is produced as a byproduct of nuclear processes like fission (splitting atomic nuclei) and fusion (combining atomic nuclei).
Blackbody Radiation
- A specific type of thermal radiation emitted by a perfect ‘blackbody’. The spectrum and intensity of blackbody radiation are determined solely by the object’s temperature.