Xinchao Wang1,Changxing Shi1,Qifan Zheng1,Jan Maroske1,Dakotah Thompson1
University of Wisconsin-Madison1
Xinchao Wang1,Changxing Shi1,Qifan Zheng1,Jan Maroske1,Dakotah Thompson1
University of Wisconsin-Madison1
We demonstrate a thermoreflectance-based thermometry technique with an ultimate temperature resolution of 60 μK in a 2.6 mHz bandwidth. This temperature resolution was achieved using a 532 nm-wavelength probe laser and a ~1 μm-thick silicon transducer film with a thermoreflectance coefficient of -4.7×10<sup>-3</sup> K<sup>-1</sup> at room temperature. The thermoreflectance sensitivity reported here is over an order-of-magnitude greater than that of metal transducers, and is comparable to the sensitivity of traditional resistance thermometers. Supporting calculations reveal that the enhancement in sensitivity is due to optical interference in the thin film.