Low temperature measurement using fluorescence thermometry

A possibility of low temperature measurement using fluorescence thermometry was examined. Temperature dependence of fluorescence lifetime applied to low temperature measurement. Chromium ion doped sapphire crystal (ruby) is known as a suitable sensor material for temperature measurement. Fluorescence thermometer using the ruby which is modified for temperature measurement has been fabricated. From this research, ruby crystal is found to be useful as the sensor head for fluorescence thermometer. In addition, the ruby crystal is potentially useful material for the sensor head crystals to measure low temperature below 273 K.