Temperature Measurements of Microhotplates Using Fluorescence Thermometry
Christopher W. Meyer, Douglas C. Meier, Christopher B. Montgomery, Stephen Semancik
A fluorescence microscope has been constructed for measuring surface temperatures of microhotplate platforms. The microscope measures temperature-dependent fluorescence lifetimes of a film of the phosphor Mg4(F)GeO6:Mn which is deposited on the microhotplate. Temperature/fluorescence-lifetime relations for this phosphor are determined by measuring the fluorescence lifetime of the phosphor-coated hot junction of a type S thermocouple while controlling and monitoring its temperature. These fluorescence-lifetime measurements have been used to determine the average temperature of microhotplates. Studies have been performed on the temperature stability of the microhotplates under steady heating and on the reproducibility of the temperatures achieved under thermal cycling. Fluorescence-intensity thermometry has been used to measure the thermal response time of microhotplates. This work demonstrates the potential of fluorescence thermometry for characterizing microhotplate performance.