Wavelength-by-wavelength temperature-independent thermal radiation utilizing an insulator-metal transition

TL;DR

This paper presents a coating that maintains nearly constant thermal radiance across a temperature range by leveraging an insulator-metal transition, enabling improved infrared imaging concealment.

Contribution

The study introduces a wavelength-specific, temperature-independent thermal radiation coating based on SmNiO3's phase transition, counteracting blackbody spectrum changes.

Findings

Radiance remains nearly constant over 20°C temperature range

Effective concealment of thermal gradients in infrared imaging

Applicable to multispectral and hyperspectral systems

Abstract

Both the magnitude and spectrum of the blackbody-radiation distribution change with temperature. Here, we designed the temperature-dependent spectral emissivity of a coating to counteract all the changes in the blackbody-radiation distribution over a certain temperature range, enabled by the nonhysteretic insulator-to-metal phase transition of SmNiO3. At each wavelength within the long-wave infrared atmospheric-transparency window, the thermal radiance of our coating remains nearly constant over a temperature range of at least 20 {\deg}C. Our approach can conceal thermal gradients and transient temperature changes from infrared imaging systems, including those that discriminate by wavelength, such as multispectral and hyperspectral cameras.