Sequential three-step three-photon near-infrared quantum splitting in β-NaYF4:Tm3+

We report on sequential three-step three-photon near-infrared (NIR) quantum splitting in Tm3+-doped beta-NaYF4, where an incident blue photon around 470nm is split into three NIR photons (1165, 1466, and 1800 nm). The underlying mechanism is analyzed by means of static and dynamic photoemission spectroscopy. Here, an experimental total quantum yield of similar to 32% is obtained. When quenching due to residual hydroxyl groups and other defect species can be overcome, numerical analyses indicate a theoretical maximum quantum yield of 158%, suggesting application in efficient spectral converters. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714505]