An investigation into the output characteristics of a discharge-heated copper vapor laser

Abstract

The laser output characteristics, such as the pulse width, peak power, pulse energy, and average power of a discharge-heated copper vapor laser, which has a discharge tube of inner diameter 4.2 cm and length 150 cm, are investigated under such conditions as the charging voltage of 14.5 kV, laser tube temperature of 1450 °C, pulse repetition rate range from 0.5 to 9.5 kHz, and buffer gas pressures of 20 and 75 Torr. Comparing the widths of the laser pulses obtained at the buffer gas of 20 Torr with that obtained at 75 Torr, it is found that the rates of relaxation of metastable atoms at these two buffer gas pressures are comparable, even though the cooling mechanisms of the electrons, the collisional deexcitation partners of metastable atoms, are different. From the dependencies of the pulse energy on the pulse repetition rate, it is found that the prepulse electron density should be higher than the value of 1013 cm−3 for efficient pumping of this laser. The dependencies of the average power on the pulse repetition rate also indicate that the output power can be increased if the pulse repetition rate is increased and the thermal insulation is optimized. This points to the possibility of improved laser output power at elevated pulse repetition rate.