Prism-enhanced wide-angle broadband nonreciprocal thermal radiation in a Weyl semimetal grating structure

Recent studies indicate that it is challenging to achieve both wide spectral and wide angular selectivity in existing structures for implementing infrared nonreciprocal thermal radiation. Therefore, it is essential to broaden the spectral coverage and angular range for different wavelengths. To overcome these limitations, a novel structure based on Weyl semimetal (WSM) and prism is designed in this study. The results show that strong nonreciprocity exceeding 0.8 is achieved in the wavelength range of 10.2-13.8µm at incident angles of 40°-80°. By studying the magnetic field distribution, the physical mechanism of broadband wide-angle nonreciprocal thermal radiation is revealed, which can be verified by impedance matching theory. Furthermore, the addition of a prism to the grating structure enhances nonreciprocal radiation and broadens the spectral range of strong nonreciprocal radiation.