Technician's instructions KEY Laser III 1243
1 Overview of functions
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1.1 Physical basics
1.1.2 What is laser radiation?
Laser radiation is an electromagnetic wave. The electromagnetic wave does not
require a material substrate for propagation.
Thus, its maximum propagation rate of c = 299,792,458 m/s is reached in the va‐
cuum. The other parameter of interest besides the speed of propagation is the
wavelength or frequency of the electromagnetic wave.
The wavelength is of great relevance for medical laser applications. The wavelength
and intensity together determine the effect on biological tissue.
Electromagnetic waves display all the characteristics a wave must possess in phy‐
sics. However, it is also possible to consider an electromagnetic wave as having a
particle character.
Photons are the particles of the electromagnetic wave. From a different point of view,
however, it is also possible to say that the particle has a wave character. This is
termed "wave-particle dualism“.
Depending on whether the wave or particle character is the essential aspect, waves
or particles (photons) are used to describe the physical processes involved in the
generation of laser radiation.
Of course, the desired wavelength can also be generated with other energy sources.
However, the selective radiation produced by a laser is characterised by the follo‐
wing three advantageous, phenomenal and essential properties:
Note
It is true that all of these features can be achieved with conventional individual
energy sources. However, the laser is the only light source that combines all of
these features.
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