Low-coherence dye laser with an intracavity radiation diffuser

Abstract

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 μ m) 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.