Enhanced 2.0 μm emission from Ho3+ bridged by Yb3+ in Nd3+/Yb3+/Ho3+ triply doped tungsten tellurite glasses for a diode-pump 2.0 μm laser

Enhanced 2.0 mu m emission from Ho3+ bridged by Yb3+ in Nd3+/Yb3+/Ho3+ triply doped tungsten tellurite glasses has been demonstrated upon excitation with an 808 nm laser diode. Nd3+ with high absorption cross section near 808 nm plays an important role in 2.0 mu m emission by transferring pump energy to Ho3+:I-5(5) level. The introduction of Yb3+ could greatly enhance the 2.0 mu m emission. The energy transfer efficiency from Nd3+ to Ho3+ and Yb3+ increases from 36.4% to 89.5% with the addition of 5mol. % Yb2O3, and the energy transfer coefficient from Nd3+ to Yb3+ (29.65 x 10(-40) cm(6)/s) is larger than that from Nd3+ to Ho3+ (3.87 x 10(-40) cm(6)/s). The underlying mechanism is analyzed by means of photoemission spectroscopy and lifetime measurement. The combination of Nd3+/Yb3+/Ho3+ could open up a possibility to realize high efficient 2.0 mu m lasing from Ho3+, which could operate at an 808 nm diode laser pump. (C) 2013 AIP Publishing LLC.