Development of nanoscale thermometry by fluorescence lifetime measurement in near-field using time correlated single photon counting

A novel noncontact and nanoscale temperature measurement method using fluorescence in near-field, namely Fluor-NOTN (Fluorescence Near-field Optics Thermal Nanoscopy) has been developed. Fluor-NOTN enables to detect the temperature dependence of fluorescence lifetime of CdSe quantum dots (Qdot) at nanoscale spatial resolution. In our case, however, the spatial resolution is limited by the sensitivity of the optical system. This paper reports the feasibility study of a proposed TCSPC (Time Correlated Single Photon Counting) to enhance the temperature measurement sensitivity of Fluor-NOTN. The experimental result indicated that Fluor-NOTN using TCSPC can measure the near-field fluorescence lifetime with 60 nm spatial resolution.