Abstract:
We present the results of an experimental study of a Tl vapour/Ar mixture as an active medium. Under optical excitation of thallium to the 6d 2D3/2 state, we have achieved lasing at λ = 1.3 μm (7p 2P01/2 –
7s2S1/2 transition) and 535 nm (7s 2S1/2 –
6p2P03/2) through cascade transitions from the 6d 2D3/2 state to the upper laser levels. The electron deexcitation rate of the
6p2P03/2 metastable state is no slower than 1.5 × 10-8 cm3 s-1, meaning that this process cannot prevent self-terminating laser action at the 7s 2S1/2 – 6p2P03/2 transition under electron-beam pumping at pulse repetition rates up to 100 kHz.