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

Abstract

Nanoscale thermometry is of paramount importance 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) centres embedded at a high concentration.Using multi-parametric analysis of photoluminescence (PL) of these centres, we have achieved an intrinsic noise floor of about 10 mK Hz −1/2 , which is a thousand-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 tem-

The challenge of intracellular temperature

“…It is about 3 μKs 1/2 for diamond (a = 50 nm) in water. For comparison, in a recent paper (Choi et al 2019), experimentally achieved record-low noise floor in all-optical measurements was about 10 mK s 1/2 . Therefore, intrinsic fluctuation of temperature is not a limiting factor even in the current state-of-the-art luminescence nanothermometry.…”

“…where k B is Boltzmann's constant. Choi et al have already discussed the formula in a recent paper (Choi et al 2019) in relation to the temperature measurements on nanoscale (see Eq.…”

Optical Nanoscale Thermometry: From Fundamental Mechanisms to Emerging Practical Applications

“…Section 2.2.1). Due to the small size, the temperature of a nanoparticle experiences fluctuations that can be quantified via the standard deviation σ th expressed as [24] T k VC V σ = th B (1) where k B is the Boltzmann constant, V is the volume of the nanoparticle, and C V is its constant volume heat capacity per unit volume. The characteristic time scale of these fluctuations, τ rel , is defined by the heat exchange between the particle and its environment.…”

“…[185,44] These specificities lead to the magnitude, and thus the sensitivity, of each method to be color-center specific. Nanothermometry techniques using silicon-vacancy (SiV), [24,45] germanium-vacancy (GeV), [44] and tin-vacancy (SnV), [46] centers are all well established. Figure 5d shows the representative example of the SiV center: spectra recorded at 288 and 302 K reveal that the ZPL peak shifts to longer wavelengths as temperature increases.…”

“…Interestingly, a multiparametric analysis scheme has been recently proposed to increase the resolution/speed of PL-based temperature measurements. [24] The scheme is mentioned here as its effectiveness-a tenfold improvement in resolution/ speed-has been demonstrated by measuring temperature via the PL signal of diamond SiV centers. Note however that the scheme is not restricted to diamond color centers and could be implemented in other systems.…”