Fotoluminiscencja

Fotoluminiscencja refers to the emission of light from a substance that has absorbed photons. This process involves the excitation of electrons within the material to higher energy levels. When these electrons return to their ground state, they release the excess energy in the form of photons, which we perceive as light. The emitted light is typically of a longer wavelength than the absorbed light, meaning it has lower energy.

There are two primary types of photoluminescence: fluorescence and phosphorescence. Fluorescence is a rapid emission of light that occurs almost immediately after excitation and ceases shortly after the excitation source is removed. Phosphorescence, on the other hand, involves a slower emission process. The excited electrons in phosphorescent materials can become trapped in metastable states, leading to a delayed and sustained emission of light even after the excitation source is gone. This phenomenon is often referred to as "afterglow."

The phenomenon of photoluminescence is utilized in various applications. Fluorescent materials are commonly found in highlighters, fluorescent lamps, and certain types of paints and inks. They are also employed in biological imaging and analytical chemistry. Phosphorescent materials are the basis for glow-in-the-dark objects, such as watch dials and emergency exit signs, where their ability to store and release light over time is essential. The specific wavelengths of absorbed and emitted light, as well as the duration of emission, depend on the chemical composition and structure of the photoluminescent material.