Measuring and controlling temperature on a reduced scale is an increasingly active area in micro and nanofluidics, more specifically when it concerns chemical and biological processes. The main motivation relies on the increased capability to obtain localized heating, strong thermal gradients and fast temperature cycling with an active control of temperature. Indeed, the design optimization of microfluidic systems takes advantage of parallelization and miniaturization where smaller volumes give rise to lower thermal mass and heat capacitance. For example, in the context of lab-on-a-chip, microfabricated polymerase chain reaction (PCR) devices^1,2  and microfluidic calorimeters^3–8  have benefited from both recent technological advances and improved methods for measuring and monitoring local temperature changes.