F2-Laser Fabrication of Fiber-Integrated Optical Elements

F 2 -lasers with their vacuum-ultraviolet emission wavelength of 157 nm offer the possibility to process UV-transparent materials like quartz or fused silica by direct laser ablation. This way optical quartz fiber tips can be modified in a way that special beam characteristics of the fiber-emitted light are generated, i.e. the beam shaping optic is integrated into the fiber. Two ablation methods for this modification of fiber tips have been developed, lateral processing and axial processing. Both are based on mask projection in combination with a rotation of the fiber. Precise shaping of the tip with surface roughness around 30 nm is obtained. Examples of these fiber integrated optics are lenses, cones or inverted cones. These functional fiber tips can be applied in medical technology or metrology.