Measuring the Elevated Temperature Dependence of Up-Conversion in Nd:YAG

Abstract

We present the measurement of the energy transfer upconversion coefficient temperature-dependence from the main upper laser level (4F3/2) of 1at.% doped Nd:YAG. This is achieved by a very simple method employing the z-scan technique, through monitoring the transmitted power of a probe laser tuned to the main absorption peak at 808 nm. In addition, to fully develop a simple model to support the measurements, we have accurately measured the temperature dependent absorption coefficient for this absorption band, covering the range from 300-450K. The spatially dependent two-level rate equation model is described, which simulates the relationship between the incident pump irradiance and power transmitted by the crystal, in function of its temperature. By comparing the experimental results with the model, we obtain a value for the energy transfer upconversion coefficient of 5.1±0.4 ×10-17 cm3/s, at room temperature, decreasing to 2.0 ×10-17 cm3/s at 450 K.