Radially polarized ring and arc beams of a neodymium laser with an intra-cavity axicon

Placing a Brewster-angle axicon inside a laser resonator makes it possible to produce a radially-polarized (RP) oscillation pattern distributed on a thin ring or a portion of a ring. Laser-diode end-pumped, Nd:Y(3)Al(5)O(12) and Nd:YVO(4) lasers were studied. Spatially coherent RP beams distributed on circular arcs were obtained with a polarization contrast ratio up to 80:1. Incoherent RP outputs on a full ring were also produced with a polarization contrast ratio of about 5:1. Applications of these beams to increase absorption efficiency in laser-matter interaction are discussed.