New ion laser transitions in copper, silver, and gold

Using hollow-cathode excitation techniques, laser oscillation is obtained at eight new transitions in copper-helium, silver-helium, and gold-helium discharges. All the transitions are in the near-infrared region and a majority of them are excited on a cw basis. Four of the transitions are obtained in Cu II, two in Ag II, and two in Au II. Lower threshold currents are also reported for five previously observed transitions.