Abstract
In principle, the absorbance of a free-standing ultra-thin film is limited to 50%. To overcome this limitation, an all-dielectric perfect absorber is proposed herein based on the concept of degenerate critical coupling (DCC) of quadrupole modes. We study the absorbance of a dielectric elliptic cylinder and find that perfect absorption can be achieved by spectrally overlapping peaks of electric and magnetic quadrupole modes. This suggests that the DCC method can be extended to the quadrupole modes beyond dipole modes. Such an all-dielectric perfect absorber can be used in photodetectors, optical filters, and optical modulators mediated by the photothermal effect.
© 2021 Optical Society of America
Full Article | PDF ArticleMore Like This
Rongyang Xu and Junichi Takahara
Opt. Lett. 46(4) 805-808 (2021)
Rongyang Xu, Junichi Fujikata, and Junichi Takahara
Opt. Lett. 48(6) 1490-1493 (2023)
Jiancun Zhao, Yan Wang, Yechuan Zhu, Wei Zhang, and Yiting Yu
Opt. Lett. 45(19) 5464-5467 (2020)