Abstract

Until 1979 it had been assumed by most workers in the field that rare earth laser emission in single-crystal hosts was limited to wavelengths shorter than 3 μm due to the overwhelming predominance of nonradiative decay over radiative decay.¹ Recently² It was demonstrated that laser emission beyond 3 μm could be generated by a combination of resonant pumping and cascade emission. In this paper we present the first description of a three-step cascade laser process. In addition all three wavelengths are in the mid-IR spectral region.

© 1982 Optical Society of America