Resonance fluorescence

Resonant fluorescence is a particular case of fluorescence, the (e.g., light) upon excitation of atoms occurs with electromagnetic waves. In this case an atom having discrete energy levels, first with a suitable photon wavelength λex is placed (for example, yellow light of the sodium D- line) in an excited state. A little later, it falls back to its ground state umd spontaneously emitted a photon of the same wavelength λem = λex.

In contrast to the fluorescent dye in more complex molecules ( eg fluorescein or green fluorescent protein) occurs here is not a Stokes shift λex - λem on between excitation and fluorescence photons.

In addition to the absorption of the photon in the atomic shell also an absorption of high-energy photons by the atomic nucleus can take place. If the core then becomes a step in the ground state, the emitted photon has the same energy. Even with a lower-energy photon is called nuclear resonance fluorescence.

See also

• Laser cooling