Quantum efficiency of Yb3+-ZnTe co-doped phosphate glass system

The present paper deals with optical properties of a highly transparent phosphate glass co-doped with Yb3+ and ZnTe nanocrystals. The presence of ZnTe nanocrystals is due to a sequential melting-nucleation procedure evidenced by optical absorption and Atomic Force Microscopy. From the perspective of compositional variation of the dopants, photoluminescence and lifetime measurements were performed. As a result, it was demonstrated that the ZnTe nanocrystals increase the Yb3+ emission by a factor up to five, when the pumping wavelength is resonant with the ZnTe absorption. It was also verified that the ZnTe nanocrystals inhibit the self-trapping of the rare earth luminescence. As a consequence, the quantum efficiency of the 5F7/2→5F5/2 transitions of the Yb3+ is considerably increased. Finally, we have found that the glass thermal diffusivity is not sensitive to temperature variations comprising the interval from room temperature to cryogenic temperatures. This can be an important property when considering this material to future applications in high-power photonic devices.