Real-Time Ratiometric Optical Nanoscale Thermometry

All-optical nanothermometry has become a powerful, remote tool for measuring nanoscale temperatures in applications ranging from medicine to nano-optics and solidstate nanodevices. The key features of any candidate nano thermometer are brightness, sensitivity, and (signal, spatial, and temporal) resolution. Here, we demonstrate a real-time, diamond-based nanothermometry technique with excellent sensitivity (1.8% K-1) and record-high resolution (5.8 x 104 K Hz-1/2 W cm-2) based on codoped nanodiamonds. The distinct performance of our approach stems from two factors: (i) temperature sensors-nanodiamonds cohosting two group IV color centers -engineered to emit spectrally separated Stokes and anti-Stokes fluorescence signals under excitation by a single laser source and (ii) a parallel detection scheme based on filtering optics and high-sensitivity photon counters for fast readout. We demonstrate the performance of our method by monitoring temporal changes in the local temperature of a microcircuit and a MoTe2 field-effect transistor. Our work advances a powerful, alternative strategy for time-resolved temperature monitoring and mapping of micro-/nanoscale devices such as microfluidic channels, nanophotonic circuits, and nanoelectronic devices, as well as complex biological environments such as tissues and cells.

Automated summary

All-optical nanothermometry is a powerful tool for measuring nanoscale temperatures in various applications. This study presents a real-time nanothermometry technique using codoped nanodiamonds with high sensitivity and resolution. The technique utilizes temperature sensors that emit spectrally separated fluorescence signals and a parallel detection scheme for fast readout. The method is demonstrated by monitoring temperature changes in microcircuits and MoTe2 field-effect transistors.