High-gain laser in Pb+populated by direct electron excitation from the neutral ground states

A high-gain laser has been observed on a transition in highly excited Pb+ (at 1.159 μm) where the population inversion between the upper and lower laser level is produced by direct electron excitation from the neutral ground state. Laser pulses were observed without the use of mirrors in a 100 cm discharge length. The single-pass gain was measured to be ∼ 17 dB/m.