Ultrasensitive All-Optical Thermometry Using Nanodiamonds with a High Concentration of Silicon-Vacancy Centers and Multiparametric Data Analysis

Nanoscale thermometry is paramount to study primary processes of heat transfer in solids and is a subject of hot debate in cell biology. Here we report ultrafast temperature sensing using all-optical thermometry, exploiting synthetic nanodiamonds with silicon-vacancy (SiV) centers embedded at a high concentration. Using multiparametric analysis of photoluminescence (PL) of these centers, we have experimentally achieved an intrinsic noise floor of about 13 mK Hz –1/2, which is a 1000-fold increase in the readout speed in comparison to the current record values demonstrated with all-optical methods of comparable spatial-resolution and precision. Our thermometers are smaller than 250 nm across but can detect a 0.4 °C change of temperature in a measurement taking only 0.001 s. The exceptional sensitivity and simplicity of these thermometers enable a wide range of applications such as temperature monitoring and mapping within intracellular regions and in state-of-the-art solid-state electronic nanodevices.