Super emitters
A super emitter is a laser that works without a resonator mirror . In an elongated laser medium in which population inversion prevails and there is a particularly high gain per length, laser activity is also possible without the feedback effect of a laser resonator.
Triggered by a spontaneous emission of a photon, it then triggers a cascade of increased spontaneous emissions when it flies approximately in the direction of the axis of the active medium. If the amplification of the laser medium is large enough, bundled laser radiation is created. This is how nitrogen lasers and TEA-CO 2 lasers typically work . Also, Nd: YAG laser and excimer laser can operate on this principle. In the opinion of some authors, super emitters are not lasers, but a separate category, namely super emitters. In superluminescent diodes , too , increased spontaneous emission occurs due to stimulated emission.
The rays of super rays are less directional and have a shorter coherence length than that of other lasers equipped with resonators.
Since most laser media do not amplify high enough to be super emitters, a laser resonator is usually necessary. The resonator consists of mirrors, which reflect the radiation again and again and thus trigger further stimulated emissions many times over.
In principle, a super emitter emits in the direction of the axis of the laser medium because sufficient amplification only occurs along that axis. So a ray emerges from both ends. Usually two methods can be used to ensure that the emission is only in one direction:
- there is a mirror at one end
- the excitation of the medium is timed along the length in such a way that amplification only takes place in one direction. This is achieved, for example, by an electrical (pump) discharge that progresses at the speed of light, see Blumlein generator .
See also
Self-amplified spontaneous emission
Individual evidence
- ↑ a b c Jürgen Eichler , Hans Joachim Eichler : Laser: Basics · Systems · Applications , Springer-Verlag , 2013, ISBN 978-3-662-22080-1 , pp. 36–37 [1]
- ↑ K. Dinstl, PL Fischer (ed.): The laser: Basics and clinical application , Springer-Verlag , 2013, ISBN 978-3-642-68008-3 , p. 50 [2]
- ↑ Friedemann Völklein, Thomas Zetterer: Practical Knowledge Microsystem Technology: Basics - Technologies - Applications , Springer-Verlag , 2008, ISBN 978-3-8348-9105-1 , p. 124 [3]
- ↑ Dirk Jansen: Optoelectronics: Basics, components, transmission technology, networks and bus systems , Springer-Verlag , 2013, ISBN 978-3-663-05975-2 , p. 70 [4]
- ↑ Andres Keller: Broadband cables and access networks: Technical principles and standards , Springer-Verlag , 2011, ISBN 978-3-642-17631-9 , p. 172 [5]