Spatial hole burning

Spatial hole burning ( English spatial hole burning ) is an effect in the physics of the laser , which causes the laser medium particular areas not constructively contribute to lasing. It is one of the two forms of hole burning .

description

In a laser with a linear resonator , i.e. a resonator with two opposing mirrors, standing electromagnetic waves are formed. The population inversion cannot be reduced at the nodes where the electric field strength is zero . "Holes" are formed, ie inactive zones in the laser medium that cannot participate in the laser process.

consequences

Atoms that are in the areas of the holes cannot be used for the laser process at the desired light frequency. This can lead to other standing waves with mostly undesired wavelengths forming in the resonator, which have their maxima approximately at the holes of the original wave.

Countermeasures

In order to prevent spatial hole burning, a ring resonator can be used instead of a linear resonator , since no standing waves are formed in it. However, a ring resonator is also more complex to adjust. It is also possible to install wavelength-selective elements in the laser that filter out undesired wavelengths.

Further information

• Spatial Hole Burning in the Encyclopedia of Laser Physics and Technology (Engl.)
• F. Kneubühl, M. Sigrist: Laser . 7th edition. Vieweg + Teubner, Wiesbaden 2008, ISBN 978-3-8351-0145-6 .