Neodymium-glass disk laser amplifier with an immersion medium

A description is given of a laser amplifier with a disk active element made of GLS2 (40×40×220 mm dimensions). This amplifier is filled with thionyl chloride (n=1.53, absorption coefficient k<10^–3 cm^–1 at λ=1.06 μ). The single-pass inactive losses, per 1 cm length of the active medium, are 4.3×10^–3 cm^–1. The results are reported of measurements of the small-signal gain and of the gain obtained at pump energy densities up to 25 J/cm³.