Development of near-field fluorescence lifetime thermometry

Accurate temperature mapping in nanoscale is essential for the thermal system design of devices. However, conventional optical thermometers cannot achieve nanoscale spatial resolution because of the diffraction limit of light. A novel superresolved optical temperature measurement technique using the near-field fluorescence lifetime is presented. The experimental apparatus based on a frequency domain fluorescence lifetime measurement method has been developed. The fluorophore was molecularly adsorbed onto the sample surface as the nanoscale temperature probe, and the temperature dependence of the fluorescence lifetime was observed. The measurement results of the temperature gradient in a micro wire heater indicate the feasibility of the proposed method.