Generation of hollow scalar and vector beams using a spot-defect mirror.

Generation of both scalar and vector hollow beams was demonstrated by using a mirror with a low-reflectivity spot to suppress the oscillation of lower order transverse modes. As scalar beams, several hollow Laguerre-Gaussian beams have been observed from a side-pumped Nd:yttrium aluminum garnet laser cavity. The intensity profiles were in an excellent agreement with theoretical ones. The phase front variation around the optical axis was verified to be spiral. Furthermore, both Laguerre-Gaussian and Bessel-Gaussian vector beams have been also observed from the identical cavity. In addition to the verification of intensity profiles, polarization pattern measurement confirmed that the beams had revolving polarization distributions along the azimuthal direction as theoretically predicted.