2 μ m lasing from highly thulium doped tellurite glass microsphere

Abstract

A single mode microsphere laser at 2μm is demonstrated from a highly thulium doped tellurite glass microsphere. Glass samples with various doping concentrations are fabricated and characterized to choose the material with the highest pump efficiency. The laser wavelength is redshifted from the emission peak of thulium ions at 1800 nm due to the different mode distribution inside the microsphere. The laser line width (full width at half maximum) is measured as 115 MHz.