Two-frequency picosecond laser based on composite vanadate crystals with σ-polarised radiation

A two-frequency picosecond laser based on α-cut Nd:YVO₄ – YVO₄ composite vanadate crystals is experimentally studied for the s-polarised radiation at the ⁴F_3/2 – ⁴I_11/2 transition with frequency tuning using Fabry–Perot etalons of different thickness. The difference between the radiation wavelengths was tuned within the range of 1.2 – 4.4 nm. In the mode-locking regime, the two-frequency radiation power was 280 mW at an absorbed pump power of 12 W.