Luminescence, up-conversion and temperature sensing in Er-doped TeO2- PbCl2-WO3 glasses

The TeO2-PbCl2-WO3:Er3+ glasses were prepared by melt-quenching technique. Optical and luminescence properties of the prepared glasses were studied by transmission and low-temperature photoluminescence spectroscopy. Emission intensities of the relevant 4f-4f transitions were studied at room temperature under 514.5 nm excitation. At low-temperatures, the broad-band emission of the host glass centered at about 1000 nm and three superimposed narrow Er3+-related emission bands were observed. Strong infrared to visible up conversion luminescence was observed under 980 nm excitation even at low erbium concentration. The observed green, red, and NIR up-conversion 4f-4f emission bands at 530, 550, 660, and 850 nm are assigned to two photon absorption processes. It follows from the study of luminescence intensity ratio of two green Er(3+)related emission bands due to transitions from thermally coupled H-2(11/2) and S-4(3/2) levels to the ground state I-4(15/2) that the studied glasses can be good candidates for non-contact optical temperature sensor applications.