A novel technique for measuring droplet temperatures has been demonstrated. Laser-induced phosphorescence from thermographic phosphors, seeded to distilled water and iso-octane, was used to measure temperatures of single falling droplets. The phosphors were excited by the fourth and third harmonics of a Nd:YAG laser. The subsequent emission was evaluated by spectral and temporal investigations of the thermographic phosphors Mg<sub>4</sub>FGeO<sub>6</sub>:Mn and La<sub>2</sub>O<sub>2</sub>S:Eu, respectively. The spectral and the temporal methods permitted temperature measurements of free-falling droplets up to 433 K. Results from both methods, which show an estimated accuracy of better than 1%, are presented.
© 2004 Optical Society of America
(120.6780) Instrumentation, measurement, and metrology : Temperature
(160.2540) Materials : Fluorescent and luminescent materials
(300.6280) Spectroscopy : Spectroscopy, fluorescence and luminescence
Alaa Omrane, Greger Juhlin, Frederik Ossler, and Marcus Aldén, "Temperature Measurements of Single Droplets by Use of Laser-Induced Phosphorescence," Appl. Opt. 43, 3523-3529 (2004)