Multiwavelength UV-IR laser system based on a-cut Nd : YVO4 — YVO4 composite vanadate crystals with σ-polarised radiation

Lasing properties of a-cut Nd : YVO₄ — YVO₄ composite vanadate crystals are experimentally studied for the p and s polarisations of radiation at the ⁴F_3/2 — ⁴I_11/2 transition. Polarisation dependences of the lasing characteristics of passively Q-switched Nd : YVO₄ — YVO₄ lasers with Cr⁴⁺ : YAG Q-switches are investigated. It is shown that the laser operates with the highest efficiency in the case of the s-polarised radiation (minimum pulse duration shorter than 1.5 ns, maximum peak power up to 25 kW, maximum peak energy about 35 μJ at a slope efficiency up to 32 %). Frequency conversion to the second and fourth harmonics is demonstrated. Based on this study, a multiwavelength laser with bactericidal and therapeutic effects is developed for treatment of a wide spectrum of diseases.