Improving Accuracy and Sensitivity of Lanthanide-Based Luminescent Manometers by Augmented Spectral Shift Method

Luminescence manometry is most often realized by a spectral shift of luminescence bands. Typically, the shift of spectrally narrow-band emission is quantified, which is highly precise but not very sensitive to pressure variations. Alternatively, the spectral shift of a broadband emission may be exploited, which is more sensitive but less precise, due to the difficulty in accurate determination of the band centroid. In this work, a mixed approach is presented, combining the shift in broadband chromium emission from the 4T2 → 4A2 level with a narrow-band neodymium emission (4F3/2 → 4I11/2 transition), observed in the La3Ga5GeO14 spectrum. The resulting optical Nd3+-based manometer demonstrates an absolute sensitivity of 2.92 cm–1/GPa for the 4F3/2 → 4I11/2 electronic transition. An additional advantage of using this material is its negligible spectral shift with temperature, determined in the T range of 77–343 K, making the pressure readouts independent of this parameter (i.e., temperature variations).