Optically pumped $Na_2$ laser

A pulsed copper vapor laser emitting the 578.2 nm line was used as the pump source in achieving stimulated emission as a result of the electronic $A{}^1\Sigma_u^+-X{}^1\Sigma_g^+$ transitions in the $Na_2$ molecule in the spectral range 0.765-0.804$\mu m$. The average power of all the emission lines was 10 mW when the pulsed pump power was 150 W and the efficiency of conversion of the optical pump energy was about 3 procent. The pulse repetition frequency was 3.3 kHz. Violet diffuse radiation of the $Na_2$ molecules, generated by pumping with the copper vapor laser, was observed. The superradiance regime was found for some of the lines.