Millikelvin-resolved ambient thermography

Abstract

Thermography detects surface temperature and subsurface thermal activity of an object based on the Stefan-Boltzmann law. Impacts of the technology would be more far-reaching with finer thermal sensitivity, called noise-equivalent differential temperature (NEDT). Existing efforts to advance NEDT are all focused on improving registration of radiation signals with better cameras, driving the number close to the end of the roadmap at 20 to 40 mK. In this work, we take a distinct approach of sensitizing surface radiation against minute temperature variation of the object. The emissivity of the thermal imaging sensitizer (TIS) rises abruptly at a preprogrammed temperature, driven by a metal-insulator transition in cooperation with photonic resonance in the structure. The NEDT is refined by over 15 times with the TIS to achieve single-digit millikelvin resolution near room temperature, empowering ambient thermography for a broad range of applications such as in operando electronics analysis and early cancer screening.

Wafer-scale freestanding vanadium dioxide film

“…The applicative temperature range of the VO 2 TIS is near its MIT temperature. Because the MIT temperature of VO 2 can be conveniently tuned from 72° to −100°C by elemental doping ( 37 , 38 ), VO 2 TIS with different applicative temperatures would be developed by using element-doped f-VO 2 films and thus finds applications in more fields such as biomedical, food safety, electronics, and so on.…”

Progress on Infrared Imaging Technology in Animal Production: A Review

“…According to the Stefan-Boltzmann Formula (1), the infrared radiation energy of an object is proportional to the fourth power of its temperature [ 40 ]. W obj = ε × σ × Τ obj 4 where W obj is the thermal radiation emitted by an object, Τ obj is the object’s temperature (measured in K), ε is the Stefan–Boltzmann constant (ca 5.67 × 10 −8 Wm −2 K −4 ), and σ is the emissivity of the object [ 42 ].…”

Smart Materials for Dynamic Thermal Radiation Regulation

“…In the future, the establishment of novel approaches may help improve the performance or widen the applications of VO 2 in MIR. For example, using a gradient doping process to obtain gradual or permanent radiance properties within a certain temperature range can realize novel thermal management, [ 44 ] or utilizing a strong, and positive temperature dependence of emissivity of VO 2 combined with proper structural designs [ 45 ] can help realize better thermal imaging. Furthermore, various types of metasurface or coupling of multiple resonances may be introduced to explore broadband [ 46 ] or dual‐band emissivity performance to enhance Δε [ 47 ] and obtain great polarization‐dependence.…”