Abstract

In many laser materials ionic dopants adopt nominally random spatial distributions. Consequently, information on energy transfer processes must be convoluted by using models for the distribution of separations between ions. For energy transfer upconversion lasers such a distribution results in some dopant ions absorbing pump excitation but being too isolated to contribute to the upconversion process. CsCdBr₃ is one of a class of novel materials that preferentially accommodate trivalent dopant ions in a single dimer configuration. The inter-ion separation of approximately 6 A enables efficient energy transfer and allows for the use of simple single-rate analysis models. This paper demonstrates the powerful use of CsCdBr₃ as a tool to unravel energy transfer processes and illustrates its potential use as an efficient and versatile upconversion laser host. Single and dual laser pumped infrared to visible upconversion investigations on Er³⁺ ion dimers and heterogeneous Tm³⁺/Pr³⁺ ion dimers are reported. Mechanisms for the excitation wavelength controlled dominance of violet, green, or red Er³⁺ emission and the mechanism for blue Pr³⁺ emission after near- IR Tm³⁺ excitation are determined.

© 1992 Optical Society of America