Differential Infrared Pyrometry for Determination of Microkelvin Temperature Variations

Precise measurement of temperature is important in studies of chemical and biological systems as reaction kinetics are almost universally sensitive to temperature. However, the use of conventional temperature probes can introduce an exogenous temperature disturbance resulting in measurement artifacts. Infrared pyrometry is a noninvasive technique for temperature measurement, however, the challenge for current infrared pyrometry is low sensitivity to small temperature variations, which in many cases precludes determination of key diagnostic information. Here, we report a sensitive differential infrared pyrometer based on spatial modulation using a resonant oscillating mirror, which enables a sensitivity to temperature variations on the microkelvin scale. The instrument is employed to monitor minuscule heat evolution in an acid–base reaction and the decomposition of H₂O₂ by bovine liver catalase. The instrument holds great promise for monitoring the dynamics of heat evolution in a range of chemical and biological systems in a completely noninvasive manner.