Various cathode design for Cu emission line in see-through hollow cathode glow discharge (st-HCGD)

We have investigated the intensity of Cu 510.6 nm emission line in see-through Hollow Cathode Glow Discharge (st-HCGD) for the development of medical Cu vapor laser. In order to acquire the stable plasma in st-HCGD cell at high current, several factors such as current, the length and the inner diameter of cathode tube, the shape of the tube, and the range of the sputtering range were tested. An optimum condition in our st-HCGD cell was obtained at 600 V, 700 mA, 2.3 Torr of Ar gas (100 SCCM), and 40 mm of tube with 4-11-4 mm type cathode design. Also, it was indirectly observed that temperature in the cell could reach more than 1000 .deg. C since Cu cathode was melt at the current more than 700 mA (melting point of Cu, 1084 .deg. C)