Precise surface temperature measurements from 400 to 1200 K using the Pr:YAG phosphor

• Published in: Applied physics. B, Lasers and optics Vol. 127; no. 12
• Main Authors: Witkowski, Dustin, Rothamer, David A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2021; Springer Nature B.V
• Subjects: Applied physics; Emission analysis; Engineering; Fused silica; Heat flux; Lasers; Optical Devices; Optics; Phosphor thermography; Phosphors; Photonics; Physical Chemistry; Physics; Physics and Astronomy; Quantum Optics; Room temperature; Silicon dioxide; Substrates; Surface temperature; Temperature; Tube furnaces
• ISSN: 0946-2171; 1432-0649
• DOI: 10.1007/s00340-021-07723-5

The thermographic phosphor Pr:YAG was investigated for lifetime-based surface temperature measurements using 4f–4f emission from its 3 P J states. A thin phosphor coating was applied to a fused silica substrate and placed in a tube furnace for diagnostic characterization. Lifetime measurements were performed from room temperature to 1200 K in 100-K increments. The emission lifetime was found to decrease continuously from 7 μ s at room temperature to 200 ns at 1200 K, making Pr:YAG a promising phosphor for applications involving fast transient phenomena. At each temperature, 100 single-shot measurements were acquired to evaluate phosphor performance. Single-shot temperature precision better than 2 K was measured from 400 to 1200 K. A methodology was developed for in-situ single-shot temperature precision estimates using weighted linear regression statistics. The precision predictions were compared to experimental results and agreement was generally within 1 K over the entire temperature range. The ability to precisely resolve temperature over large ranges in an applied environment was demonstrated using a propane torch to expose the phosphor-coated substrate to high heat fluxes. Measured temperature increased from room temperature to approximately 1150 K during the experimental duration, with estimated precision better than 4 K over the entire range