lighttransmittanceemission

Light transmittance and emission are fundamental optical properties of materials. Transmittance refers to the ability of a material to allow light to pass through it. This is typically measured as a percentage, indicating how much of the incident light emerges on the other side. Materials can be transparent, allowing clear passage of light, translucent, scattering light as it passes, or opaque, blocking light transmission entirely. The wavelength of light also plays a crucial role; a material might be transparent to visible light but opaque to ultraviolet or infrared radiation.

Emission, on the other hand, is the process by which a material releases energy in the form of photons (light). This emission can occur through various mechanisms. Incandescence, for instance, is the emission of light due to high temperature, as seen in incandescent light bulbs. Luminescence encompasses a broader range of light-emitting phenomena not primarily driven by heat. This includes fluorescence, where a material absorbs light of one wavelength and re-emits it at a longer wavelength almost instantaneously, and phosphorescence, which involves a delayed re-emission of light after the excitation source is removed. Electroluminescence is the emission of light in response to an electric current, a principle used in LEDs. Understanding both transmittance and emission is vital in fields ranging from material science and optics to lighting design and display technology.