Direct generation of a first-Stokes vortex laser beam from a self-Raman laser

We demonstrate the direct generation of a first-order LG(01) Laguerre Gaussian (vortex) mode operating at the first-Stokes wavelength of a diode end-pumped, Nd: GdVO4 self-Raman laser. To the best of our knowledge, this is the first report of intracavity stimulated Raman scattering (SRS) being used as a method for frequency conversion of a vortex laser beam and it is effective in enabling the frequency-converted (Stokes) beam to have the same LG(01) mode as the fundamental beam. (C) 2013 Optical Society of America