Abstract

Upconversion pumping of solid state lasers has been of increasing interest in recent years, since it allows laser operation at shorter wavelengths (eg., the blue) with a longer wavelength pump (e.g., the red or infrared). Pumping at longer wavelengths allows diode lasers to be used, and also avoids the possibility of defect formation associated with ultra-violet excitation. Tm³⁺ is of particular interest as the active ion because of its widely spaced energy levels throughout the infrared, visible, and ultraviolet. Upconversion lasers based on "Tm³⁺ have now been demonstrated both in bulk crystals^1,2 and in glass fibers.^3–5

© 1993 Optical Society of America