  All optical nanothermometry has become a powerful, noninvasive tool for
measuring nanoscale temperatures in applications ranging from medicine to
nanooptics and solid-state nanodevices. The key features of any candidate
nanothermometer are sensitivity and resolution. Here, we demonstrate a real
time, diamond based nanothermometry technique with sensitivity and resolution
much larger than those of any existing all optical method. The distinct
performance of our approach stems from two factors. First, temperature sensors
nanodiamonds cohosting two Group IV colour centers engineered to emit
spectrally separated Stokes and AntiStokes fluorescence signals under
excitation by a single laser source. Second, 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 lays the foundation 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.
