Determine diamond sample surface emissivity for accurate infrared thermometry

Determine the actual surface emissivity of the chemical-vapor-deposited diamond sample containing negatively charged nitrogen-vacancy (NV) centers at the infrared wavelength band used by the FLIR T650sc infrared thermal imager, so that radiation thermometry can yield accurate true surface temperatures during microwave irradiation experiments.

Background

The study measures heating of diamond samples with NV centers under various microwave irradiation schemes and uses an infrared thermal imager (FLIR T650sc) alongside thermocouples. Accurate temperature extraction from infrared images via radiation thermometry requires knowledge of the sample’s surface emissivity at the imager’s wavelength band.

The authors state that accurate information on the actual emissivity of the diamond sample is unknown, leading them to use the instrument’s default emissivity. This limits the infrared measurements to reliable relative thermal contrasts rather than precise absolute temperatures, motivating a concrete need to determine the sample’s emissivity for robust quantitative thermometry.

References

The real surface temperature of the sample is extracted using a radiation thermometer, depending on accurately knowing the sample surface emissivity at the corresponding wavelength. However, the accurate information on the actual emissivity of the diamond sample is unknown.

— Microwave heating effect on diamond sample of NV centers  (2203.07906 - Wang et al., 2022) in Main text, paragraph discussing infrared emissivity in the description of Fig. 2a (Temperature spectra for CW-ODMR)