Abstract

Microsphere cavities offer appealing advantages for applications as miniature light sources due to their small size, high quality factor and low mode volume. Active spheres can be fabricated from glass doped with rare-earth ions such as Er³⁺ and Yb³⁺. The close proximity of energy levels in these triply-ionized ions is of particular advantage for obtaining fluorescence emissions through various upconversion mechanisms [1]. Here we report the first observation of chromatic and intensity optical bistability (OB) in a commercial, active, phosphate glass (Schott IOG-2) microsphere driven by thermal avalanche at room temperature. This is, to the best of our knowledge, the first report of simultaneous intensity OB (at multiple wavelengths) and chromatic OB in a single material.

© 2007 IEEE