@incollection{Rai12, author = {Vineet Kumar Rai}, title = {Frequency Upconversion in Rare Earth Ions}, booktitle = {Solid State Laser}, publisher = {IntechOpen}, address = {Rijeka}, year = {2012}, editor = {Amin H. Al-Khursan}, chapter = {7}, doi = {10.5772/36197}, url = {https://doi.org/10.5772/36197} }