Kokonaisabsorptio

Kokonaisabsorptio, often referred to as total absorption, is the complete uptake of incident energy by a material or system, such that no energy is reflected or transmitted. In wave physics this energy can be electromagnetic radiation, sound, or particles. The absorbed fraction is commonly described by A = 1 − R − T, where R is reflectance and T is transmittance.

Total absorption is achieved in theory when both reflection and transmission are zero (R = 0 and T = 0), yielding A = 1. In practice, engineers strive for very high absorption within a specified frequency or wavelength range. Real-world implementations rely on design strategies that enhance coupling of the incident energy into the material and convert it into other forms, typically heat.

Common approaches to achieve high or near-total absorption include impedance matching between the absorber and its surroundings, critical coupling conditions, and the use of lossy layers, metamaterials, or multi-layer stacks. Some designs employ a backing reflector to suppress transmission while maintaining strong absorption in a thin layer.

Applications of kokonaisabsorptio concepts appear across optics, acoustics, and thermal management. In optics and photovoltaics, high absorption improves detector sensitivity and solar energy harvesting; in acoustics, it reduces noise; in thermal engineering, it enables efficient radiative heat management. The concept is inherently frequency-dependent, and achieving broadband total absorption often requires complex, carefully engineered structures.