Improving Optical Temperature Sensing Performance of Er Doped YO Microtubes via Co-doping and Controlling Excitation Power.

This work presents a new method to effectively improve the optical temperature behavior of Er doped YO microtubes by co-doping of Tm or Ho ion and controlling excitation power. The influence of Tm or Ho ion on optical temperature behavior of YO:Er microtubes is investigated by analyzing the temperature and excitation power dependent emission spectra, thermal quenching ratios, fluorescence intensity ratios, and sensitivity. It is found that the thermal quenching of YO:Er microtubes is inhibited by co-doping with Tm or Ho ion, moreover the maximum sensitivity value based on the thermal coupled S/H levels is enhanced greatly and shifts to the high temperature range, while the maximum sensitivity based on F/F levels shifts to the low temperature range and greatly increases. The sensitivity values are dependent on the excitation power, and reach two maximum values of 0.0529/K at 24 K and 0.0057/K at 457 K for the YO:1%Er, 0.5%Ho at 121 mW/mm excitation power, which makes optical temperature measurement in wide temperature range possible. The mechanism of changing the sensitivity upon different excitation densities is discussed.