Vanadate lasers with σ-polarised radiation

Luminescent and lasing properties at the ⁴F_3/2 — ⁴I_11/2 transition of α-cut Nd:YVO₄, Nd:GdVO₄, Nd:Gd_1-xY_xVO₄ and Nd:Sc_1-xY_xVO₄ vanadate crystals are experimentally studied for π- and σ-polarisations. Polarisation dependences of the lasing characteristics of passively Q-switched Nd:YVO₄, Nd:Gd_1-xY_xVO₄ and Nd:Sc_1-xY_xVO₄ lasers with Cr⁴⁺:YAG and V³⁺:YAG Q-switches are investigated. It is shown that the laser wavelengths are different for π- and σ-polarizations. The best characteristics are achieved for the Nd:YVO₄ laser with a Cr⁴⁺:YAG passive saturable absorber for σ-polarisation (minimum pulse duration shorter than 3 ns, maximum peak power up to 10 kW, maximum peak energy ~35 μJ at a slope efficiency up to 32%).