2024 | Komron J. Shayegan, Jae S. Hwang, Bo Zhao, Aaswath P. Raman, and Harry A. Atwater
The paper by Komron J. Shayegan, Jae S. Hwang, Bo Zhao, Aaswath P. Raman, and Harry A. Atwater demonstrates broadband nonreciprocal thermal emissivity and absorptivity in gradient epsilon-near-zero (ENZ) InAs layers. The researchers measured the thermal emissivity and absorptivity of these layers under an external magnetic field, achieving an inequality in spectral directional emissivity and absorptivity over a wide spectral range (12.5–16 μm) that overlaps with the infrared transparency window. The effect is observed at moderate magnetic fields (1 T) and is attributed to the unique properties of ENZ materials, where the permittivity scalars transform into anti-symmetric tensors under magnetic fields. The study shows that the nonreciprocal tuning of emissivity and absorptivity depends on the sample's subwavelength thickness and carrier concentration ordering. The results provide a platform for future work on spectrally tailored, directionally selective nonreciprocal emitters, which could have applications in photonic energy conversion and radiative cooling.The paper by Komron J. Shayegan, Jae S. Hwang, Bo Zhao, Aaswath P. Raman, and Harry A. Atwater demonstrates broadband nonreciprocal thermal emissivity and absorptivity in gradient epsilon-near-zero (ENZ) InAs layers. The researchers measured the thermal emissivity and absorptivity of these layers under an external magnetic field, achieving an inequality in spectral directional emissivity and absorptivity over a wide spectral range (12.5–16 μm) that overlaps with the infrared transparency window. The effect is observed at moderate magnetic fields (1 T) and is attributed to the unique properties of ENZ materials, where the permittivity scalars transform into anti-symmetric tensors under magnetic fields. The study shows that the nonreciprocal tuning of emissivity and absorptivity depends on the sample's subwavelength thickness and carrier concentration ordering. The results provide a platform for future work on spectrally tailored, directionally selective nonreciprocal emitters, which could have applications in photonic energy conversion and radiative cooling.