Amplified spontaneous emission on the J=2->1,3p-3s transition of neonlike argon in a capillary discharge

We report the observation of amplified spontaneous emission on the J=2-->1, 3p-3s transition (C-line) of neonlike argon at 69.78 nm in capillaries of 6-mm bore. The simple discharge is driven by a small capacitor bank having a capacitance of 0.1 mu F. Gain coefficients between G=0.17 cm(-1) and G=0.25 cm(-1) are derived.