Tm-Ho Co-doped System: Challenges and Solutions for Enhanced Laser Performance

The Tm-Ho co-doped system presents a challenge due to its quasi-three-level nature, which results in thermal population of the lower laser level of Ho3+. This leads to a higher ground-state population, which in turn causes severe reabsorption loss and an increase in up-conversion rate, particularly when CHo is high. To enhance laser performance, it is essential to reduce CTm and CHo, which can significantly decrease reabsorption loss and up-conversion rate.