V4+ in Corundum: Crystal Growth and Spectroscopy

Transition metal ions with the d1 or d9 electronic configuration, such as Ti3+, V4+ and Cu2+, are of particular interest for tunable solid state lasers. In these ions, the existence of basically only one high-lying excited state determines the absence of internal transitions that could produce excited state absorption. Ti3+ in corundum is an example of a successful system. V4+ in the same host looks also very promising.1