Advances in up-conversion lasers based on Er3+ and Pr3+

The present work gives an overview of room-temperature up-conversion laser systems operating in the visible spectral region. In addition to the theoretical description of the up-conversion and photon-avalanche up-conversion mechanisms, two rare-earth ions in fluoride hosts are presented in detail: erbium and praseodymium. Using a multi-pass pumping set-up, green erbium up-conversion lasing at 552 nm is demonstrated in LiLuF4 under laser-diode pumping. In addition, laser operation of three different ytterbium co-doped praseodymium systems at several wavelengths is presented. A common property of the host materials LiLuF4, LiYF4, Bay(2)F(8), and ZBLAN is their low phonon energy, which makes them favorable for up-conversion and photon-avalanche up-conversion laser systems. (C) 2004 Elsevier B.V. All rights reserved.