jälkikiilto

Jälkikiilto is a Finnish term that translates to "afterglow" or "aftershine" in English. It is most commonly used in the context of materials science and optics to describe a phenomenon where a surface continues to emit light for a period after the initial excitation source has been removed. This can occur in various materials, including phosphors, luminescent paints, and certain plastics. The duration and intensity of the jälkikiilto depend on the specific properties of the material, such as its chemical composition and the energy of the excitation source.

The mechanism behind jälkikiilto typically involves the absorption of energy, which excites electrons in the material to higher energy levels. When these electrons return to their ground state, they release the absorbed energy in the form of photons, resulting in light emission. This process is known as luminescence, and jälkikiilto specifically refers to the light emitted after the primary excitation source is switched off. Different types of luminescence, such as phosphorescence and fluorescence, can contribute to or exhibit afterglow.

Applications of materials exhibiting jälkikiilto are diverse. They are found in safety signage, exit signs, emergency lighting, and glow-in-the-dark toys and decorations. The ability of these materials to store light energy and release it gradually makes them useful in situations where visibility is crucial, even in the absence of external light sources. The development of new materials with enhanced and longer-lasting jälkikiilto properties is an ongoing area of research in material science.