Generation of a Fiber Laser Beam

Laser beams are generated by exciting the atoms of a medium, such as a crystal, gas, or liquid to generate light of a certain wavelength. Light must be amplified before it leaves the medium. In many laser configurations, the process takes place in more than one stage. The wavelength of the outgoing beam depends on the excitement of the atoms and therefore on the material properties of the medium. The above simplified diagram demonstrates the process of generating fiber lasers where a specially doped optical fiber provides the medium for amplification.

Mirrors and lenses are used to direct and focus the laser beam to individual points on a target. This creates high-contrast and high-quality marks as the beam hits the material surface. By using different laser marking processes, it’s possible to create a mark only on the surface, deep into the material, or under the surface. It’s also possible to create a mark by removing a coating (such as paint or corrosion) from the surface.

Differences between Laser Marking Systems

The main difference between laser systems is the wavelength of the laser beam. Stimulating the atoms of different material atoms release an energy in the form of electromagnetic waves.

The material type determines which wavelength is produced by your laser. For example, some solid-state lasers use Nd:YAG crystals to produce light. These crystals release a wavelength of 1,064 nanometers (or 1.064 microns). The wavelength of the light from a UV laser is 355 nanometers and the wavelength of the CO2 lasers is 10,600 nanometers (or 10.6 microns).  

The light absorption properties of surfaces are different and therefore, different laser types with different wavelengths must be used. For example, fiber lasers can be used to mark metals and CO2 lasers work better on the organic materials such as wood and plastic.

 Different lasers can also release energy differently. You can either use a continuous-wave laser or a pulsed laser. Whereas continuous-wave lasers continuously emit the laser beam, pulsed lasers release the beam at a set rate. Pulsed lasers can reach higher peaks of energy density because they charge up energy before releasing it. They’re ideal for laser marking applications because they offer a higher making speed. Continuous lasers are more adapted to other laser applications like laser cutting, welding, and drilling.