Low-coherence dye laser with an intracavity radiation diffuser.

Study of a low-coherence dye laser is reported. A cuvette with a 2 mm gap containing a dense mixture (slurry) of LiF crystal granules (70-140 µm) and an immersion liquid with a dye dissolved in it was installed in a double flat mirror cavity as an active element and simultaneously as a diffuser of radiation. The parallel light beam experiences losses in such a cuvette due to refraction at a set of interfaces between solid particles and a liquid in which different parts of the beam are randomly deflected at small angles. Measurements of the loss coefficients, angles of rays' deflection in the cuvette-diffuser were carried out. When this cuvette was pumped by 25 ns pulses of the 2nd harmonic of a Nd:YAG laser, 20 ns pulses of radiation in the region of 550-650 nm with energy ≈1 mJ at a beam divergence 5-80 mrad, and a degree of spatial coherence γ ≲ 0.1 were obtained in slurry with PM567, Rh101 or DCM dyes. The features of spectra and spatial-angular characteristics of these slurry lasers are discussed, tuning of the spatial coherence of radiation is demonstrated. Possible applications of a dye laser with an intracavity diffuser as a source of low-coherence radiation are considered.

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.