Direct generation of the first-radial-order Laguerre-Gaussian mode in a Nd:YVO(4)laser incorporating a core-ring-shaped pump fibre

Abstract

We report a diode-end-pumped Nd:YVO(4)laser with a first-radial-order Laguerre-Gaussian (LG(10)) mode output by using a pump beam shaping scheme. A simple method for conditioning the diode pump beam using a core-ring-shaped pump fibre allows selective excitation of the LG(10)mode in the Nd:YVO(4)laser resonator, yielding 0.35 W of continuous-wave output in a core-ring-shaped LG(10)mode beam with a beam propagation factor (M-2) of ˂3.2. The corresponding slope efficiency with respect to the incident pump power was 21%. We also investigated the beam propagating characteristics of the LG(10)mode beam showing that the core beam of the LG(10)mode has a smaller focused beam size accompanied by lower divergence, compared with the TEM(00)mode beam. The prospects for further power scaling and generation of a higher order LG(p0)mode are discussed.