cw helium-neon Raman laser

Continuous lasing has been observed at 650 nm with a helium-neon electrical discharge placed in an ultrahigh finesse optical cavity. This new lasing line is attributed to a Stokes–Raman process between the 1s5 and 1s4 electronic states of neon atoms pumped by the 632.8-nm neon lasing line. A gain calculation based on a near-resonant stimulated electronic Raman process predicts a lasing threshold for the 650-nm line near that measured. Lasing output power was measured as a function of discharge current and helium-neon gas pressure for the pump line and for the Stokes line.