Reconfigurable infrared (IR) materials have widespread applications in thermal management and smart IR concealment. Although various reconfigurable IR materials can be customized by positive or negative differential VO2-based resonators, their insightful mechanism remains unknown. Here, we comprehensively investigate the fundamental design rule of reconfigurable thermal radiation between positive and negative differential thermal radiation properties for the first time. Importantly, the skin depth of VO2 film in the metal state is investigated to clarify the transformation from positive to negative differential thermal radiation properties, and the critical thickness is further derived, providing important guidance in designing the reconfigurable thermal radiation regulator. Furthermore, the reconfigurable multistate thermal images had been presented into one plate. The resulting emittance variation (△ε8-14 μm) of the VO2-based resonator can change from 0.61 to -0.53, which consummates the ability for diverse demands such as infrared concealment, thermal illusion, and thermal management. This work constitutes a promising and universal route toward designing whole smart devices and may create new scientific and technological opportunities for platforms that can benefit from reconfigurable electromagnetic manipulation.
Keywords: Fabry−Pérot resonator; reconfigurable; thermal radiation; thickness; vanadium dioxide.