Fibers for Material Processing

Fibers for Material Processing

The use of lasers in material processing includes cutting, welding or writing. How well a material absorbs a specific energy depends on the wavelength dependent absorption coefficient of the material. The wavelength of the laser can be chosen to fit to a high absorption range of the material that is to be processed. Fiber lasers consist of an active fiber , which converts the pump light into laser light.

In order to transport light from the laser source to the desired working point an optic path needs to be created. This path consist of an optical fiber , lenses, prisms, mirrors, windows or a combination of these optical components . The used material depends on the wavelength of the laser. For lasers working in the visual spectral range, e.g. YAG-Lasers working with 532nm, fused silica is the prime material to use. Especially in higher power laser applications the low absorption coefficient of fused silica reduces the chance of local heat generation, which can distort or destroy the optical component. In these cases as well as for UV and deeper UV (DUV) applications, In addition to the low absorption, higher temperature stability and high damage resistance are important in laser applications.
More information on fused silica properties

Optical fibers that guide the laser light from the laser to the focusing optics head, typically have a large core. This reduces the power density in the glass, which reduces the risk of light induced damage. In addition, certain grades of fused silica are more resilient to laser induced damage than others.

During processing, fumes and debris from processing can be emitted from the processing plane and get in contact with the laser head that contains the optics. Many laser manufacturing optics use AR (anti reflex) coated windows as cover plates or debris shields . These small discs are a consumable, yet their properties influence the overall system performance.

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