How a (dental) laser works

With the help of the laser, electromagnetic waves are strengthened and aligned. Thus, a high energetic light beam is obtained that can be used selectively to cut or burn (e.g. cutting into the gums or tongue, burning of hair follicles as a hair removal method, heating up of therapeutic gels, etc.) the area designated for treatment.

The laser’s selective usability is possible due to its unique wavelengths (often recognizable by the color of the light). This is different for each laser type used.

Various tissues have their own absorption rate at different wavelengths. Therefore, the choice of laser is dependent on the treatment to be performed. For instance, the KTP laser has a wavelength of 532 nm. Its light is highly absorbed by hemoglobin and oxyhemoglobin which makes it well suited for minor surgical procedures with a perfect haemostasis.
The laser is defined by the medium that it employs to strengthen its light. This medium can be a gas, but also a liquid or solid.

An external energy source transmits the electric or light energy to the atoms of the substance (medium) producing laser light. Consequently, if the photons are sent out traveling in the same direction between two mirrors, the intensity of the bundle increases. This occurs because the atoms constantly release photons with the same wavelengths, and at the same phase, as the passing photons: The bundle is then called coherent.