Abstract

In Ref. 1 authors supported that a four-fold coordinated four-valent chromium ion ${\text{Cr}}_{\text{t}}^{4+}$ may be used as a sensitizer of luminescence of some rear-earth ions in YAG crystal, but no oscillation experiments had been performed. For the first time we report about laser action on the ³H₄→ ³H₆transition of Tm³⁺ion when it is excited due to energy transfer from ${\text{Cr}}_{\text{t}}^{4+}$ions.

© 1994 IEEE