ABSTRACT
Dye lasing in a dense slurry-like mixture, similar to the optical medium of the Christiansen filter, is first reported. A cuvette with lithium fluoride (LiF) crystal particles and an immersion liquid containing pyrromethene 567 dye was placed in a two plane mirror resonator and pumped by pulses of the second harmonic of the neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. Twenty nanosecond pulses at 545-570 nm wavelengths with energies up to 0.6 mJ were obtained at the output of this slurry laser. The central part of the laser beam with a divergence of 6 mrad was usually accompanied by a ring structure of scattered radiation. The conditions of the generation development and formation of the output beam profile in a slurry laser as well as its possible applications are discussed.
ABSTRACT
We demonstrated the operation of cw diode-pumped Yb:YAG laser in radial or azimuthal polarized (RP or AP) beams using a combination of birefringent uniaxial crystal (c-cut YVO4 or α-BBO) and lens as intra-cavity elements. RP and AP doughnut modes (M2 = 2-2.5, polarization extinction ratio 50-100:1) with output power up to 60 mW were generated. Apart from doughnut modes, RP or AP ring-like off-axis oscillations and multi-ring beams with mixed RP and AP were also observed at the output of this laser scheme. Using intra-cavity short focus lenses with spherical aberrations AP or RP modes of higher orders was obtained. Mechanism of mode selection in the laser is discussed. The large variety of beams with axially symmetric polarizations from the output of the proposed laser scheme may find applications in different fields.
