Investigation of the summation of copper-vapour laser frequencies

An investigation was made of the conversion of the copper-vapour laser radiation ( λ₁ = 0.51 μm and λ₂ = 0.578 μm) into UV radiation at the sum frequency (λ₃ = 0.271 μm) in a DKDP crystal. The operation of this frequency converter was compared for two magnifications of the laser cavity: M = 5 and 200. The best results were obtained for M = 200 (average UV radiation power 0.75 W, conversion efficiency 12%). A study was made of the characteristics of the formation of radiation pulses representing the two lines in the laser beam as a whole and in its weakly diverging core. In a low-divergence beam the yellow- and green-line pulses were emitted practically simultaneously with approximately the same peak power, which facilitated the sum-frequency generation.