The is a fundamental physical parameter that quantifies how effectively a medium absorbs energy—typically in the form of light or sound—as it passes through. Represented by the Greek letter
: In semiconductors, photons with energy below the "band gap" are not absorbed at all, making effectively zero for those wavelengths. absorption coefficient
means a material absorbs light more efficiently over a shorter distance. For instance, tinted windows have a higher absorption coefficient than clear ones. The is a fundamental physical parameter that quantifies