Abstract

Efficient room temperature lasing has been demonstrated in Tm:Lu3Al5O12 (Tm:LuAG) operating as a quasi-two level laser. Tm: LuAG pumped at the 3F4 manifold with 1.75-μm radiation has shown efficient lasing from the same manifold in the 2-μm region. Tmdasers, commonly pumped at the 3H4 manifold with 0.78-μm laser diodes, can potentially produce two 2-μm photons from one pump photon resulting on high efficiencies. Due to the large number of resonant transitions of Tm ions in laser materials, the mechanism by which the 0.78 pm diode laser pump light is converted to 2 pm radiation has many loss processes. These loss processes may be avoided by directly pumping the 3F4 manifold which contains the upper laser level. Tm:LuAG was chosen for this investigation since the splitting of the manifold containing the lower laser level has been predicted to be larger than for other garnets.1 This feature results in a lower thermal population of the lower laser level facilitating inversion. This paper discusses the performance of a quasi-two- level Tm:LuAG laser.

© 1994 Optical Society of America