Near-field radiative modulator based on dissimilar hyperbolic materials with in-plane anisotropy

摘要

Rotating relatively between the emitter and the receiver has been proposed as an effective way to modulate the near-field radiative heat transfer between anisotropic media. However, the modulation contrast, which is the most important parameter to measure the modulation effect, has not been greatly enhanced. Here we study the near-field radiative heat transfer between dissimilar hyperbolic materials α-MoO_3 and hexagonal boron nitride (hBN). The numerical results indicate that the modulation contrast in this work can reach a value higher than 12.45, which is larger than the value obtained in published literature. The energy transmission coefficient and the imaginary part of the reflection coefficient are used to explore the modulation mechanism. It is found that the large modulation contrast is attributed to the mismatching of hyperbolic volume phonon polaritons in the type I hyperbolic band of hBN by the relative rotation. This work provides a new approach to designing high performance near-field radiative modulators.