Abstract

We report the sudden appearance of upconversion fluorescence and resonant increasing absorption above a threshold intensity in Tm YALO₃ at room temperature. These effects are shown to arise from nonlinear, cooperative, excited-state dynamics. Comparison with quantum theory reveals essential roles both for pairwise cross relaxation and excitation migration among Tm impurity ions.

© 1991 Optical Society of America

Infrared-to-ultraviolet photon-avalanche-pumped upconversion in Tm:LiYF₄

A. W. Kueny, W. E. Case, and M. E. Koch
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Nonlinear dispersion of avalanche upconversion

Q. Shu, H. Ni, and S. C. Rand
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