Abstract

Significant progress in the development of solid-state lasers based on the Ho³⁺ ion has been made within the last few years. A particularly useful system is Υ₃Αl₅O₁₂:Ηο³⁺ codoped with the Cr³⁺ and Tm³⁺ dopants, which allow for the efficient sensitization of the Ho laser ions in a flashlamp-pumped laser design.¹ On the other hand, only the Tm sensitizers are required for AlGaAs laser diode-pumped systems (including the Y₃Al₅O₁₂ and LiYF₄ hosts).^2,3 The crucial Tm and Ho energy transfer processes involve the so-called "two-for-one" cross relaxation of Tm, the Tm → Ho energy transfer step, and the Auger upconversion of Ho,⁴ (illustrated in Fig. 1). In this work we will focus on the Tm → Ho energy transfer step,³ although the new insights that are developed suggest a way to minimize the undesirable Auger upconversion.

© 1992 Optical Society of America