The laser source consist of a resonator inside which the electrons of the active medium (e.g. NdYag crystals, Ytterbium fibers or CO2 mixtures) are excited through the energy provided by the pump, e.g. lamps, laser diodes, electrical discharges or radio frequencies.
The excitation state is an unstable condition and therefore after a predefined time the electron returns to the ground state; this decay leads to the emission of a photon that triggers the cascade emission of photons by all the excited electrons of the active medium. All these photons will be replica of the first, giving rise to a monochromatic, coherent, unidirectional and collimated beam ... in short, a laser.
To ensure high energies from the source, the photons are bounced between two mirrors so that as they cross the active medium, an increasing number of photons is emitted. To allow the laser beam output and therefore to be able to use it, the front mirror of the resonator is partially reflective. The operating modes of the laser are summarizable to two macro-families, continuous (called Continuos Wave) and pulsed operation. The pulse mode can be obtained either through the modulation (on-off) of the source or, alternatively, through the Q-switching which allows to obtain very high peak energies. To convert a physical reaction into a production technology, all you need to do is moving the beam and so turn it into a luminous tool.
Since we are talking about tools of light, the tool holders used are mirrors. Mirrors mounted on linear drives, such as in cutting portal systems, or angular, like in galvanometric marking systems, or in manual handpieces are the most common solutions.
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