Answers are grounded in this paper and cite their sources.
We observe guided blue and green upconversion fluorescence in an ion-exchanged waveguide that is fabricated in an erbium-ytterbium-codoped silicate laser glass. The guides are optically pumped at room temperature by using a Ti:sapphire laser with lambda = 880-980 nm; the observed fluorescence is in two bands, 480-490 and 520-560 nm, and results from multiphoton excitation.
No takes yet. Share an insight, caveat, or question.
Jackel et al. (1992) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: