Generation, amplification and characterization of cylindrical vector beams in optical fibers

Laser technology makes it possible to generate and manipulate light in a controllable way. Thus the beam properties can be tailored to the specific requirements of the application in order to enhance the performance or throughput of the process. In this context, a wide range of applications present a circular symmetry which would, therefore, profit from a beam with the same symmetry characteristics in both its intensity profile and polarization distribution. Such a symmetry is found in azimuthally and radially polarized cylindrical vector beams, which are of special interest for many applications and, thus, subject of this thesis. In the first part of this work a novel and universal characterization method, which results in a so-called quality vector, is presented in order to determine the properties of complex beams independently of their intensity profile and spatial polarization distributions. This quality vector quantitatively determines the characteristics of the beam and presents them in a compact way. In the context of this work this tool is employed for the characterization of cylindrical vector beams. The second part of this work presents the generation cylindrical vector beams with the help of a fiber-based mode filter. The integration of this element in an Yb-doped or Raman fiber oscillator is also presented and discussed. The generation of cylindrical vector beams with this technique can be carried out in a wide wavelength range, which is very attractive for realizing monolithic light sources for microscopy applications with resolutions beyond the diffraction limit. Finally, the last part of this work presents and discusses the amplification of pulsed cylindrical vector beams in a few-mode rod-type photonic crystal fiber to power levels suitable for material processing.