He-Ne laser generation of 1.15-1.20 microns in a hollow copper cathode

The generation of 1.15, 1.16, and 1.20-micron He-Ne laser lines in a hollow copper cathode has been studied experimentally over a wide range of gas pressures and He/Ne ratios. It is shown that the optimum conditions for lasing at a current density of 25 mA/sq cm are He/Ne = 60/1, a total gas pressure of 20 Torr, and pd = 52 Torr mm (where p is the gas pressure and d is the slotwidth). A small-signal gain factor of 45%/m has been measured at a current of 1.5 A for optimum generation conditions, without considering the resonator losses. Lasing at 1.15 micron has been also obtained in pure Ne.