Intense 2.7 mu m Emission, Lifetime and Mechanism of Er3+:LaF3 Nanocrystals Embedded Germanate Oxyfluoride Glass Ceramics

摘要

Efficient 2.7 mu m mid-infrared emission was obtained in Er3+: LaF3 nanocrystals embedded germanate oxyfluoride glass ceramics (GCs), which were fabricated by conventional melt-quenching and subsequent thermal treatment. X-ray diffraction (XRD) and transmission electron microscope (TEM) indicated LaF3 nanocrystals emerged in the germanate glass matrix. Absorption and transmittance spectra were carried out to evaluate the content of hydroxyl groups (-OH) which is known as the quenching center of 2.7 mu m emission in glasses. Intense 2.7 mu m mid-infrared and 1.5 mu m near-infrared emissions were achieved upon the excitation of a 980 nm laser diode, and the fluorescent lifetime of Er3+: I-4(11/2) level (2.7 mu m emission) was recorded in GCs. Interestingly, it is found that the fluorescent lifetime of upper I-4(11/2) level is longer than that of lower I-4(13/2) level, which is vital for the subsequent 2.7 mu m laser output from Er3+: LaF3 nanocrystals embedded GCs. Based on these results, a circulatory energy transfer mechanism was proposed to demonstrate the energy transfer between adjacent Er3+ ions.