Abstract
An erratum is presented to correct the wrong picture in our paper.
© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
A wrong figure was used in our paper [1]. The Fig. 3 is the same as Fig. 2. The correct Fig. 3 (here Fig. 1) shown below describes the emission cross sections of Ho:GTO crystal. This mistake does not affect the conclusions of the paper. We apologize for any confusion this may have caused.