Regular Article – Optical Phenomena and Photonics
Ultrastrong Purcell enhancement of magnetic dipole emission based on quasi-BIC
School of Mechanics and Photoelectric Physics, Anhui University of Science and Technology, 232001, Huainan, China
Accepted: 27 October 2022
Published online: 7 November 2022
Here, we propose a hollow quasi-periodic spoof plasmonic structure to realize the ultrastrong Purcell enhancement of magnetic dipole emission in terahertz frequency range based on quasi-bound states in the continuum. By independently tuning the substructures, we can severally tune the responses of the electric dipole and quadripolar modes supported by groove-substructure, and the magnetic dipolar mode supported in slit-substructure. In particular, we also observe a whispering gallery mode supported by the composite structure, which will move with changing structural parameters. When the magnetic dipole mode close to the whispering gallery mode, the interference between them will emerge to generates a quasi-bound state in the continuum with ultra-high quality factor. Then, based on the quasi-periodic structure, we put a magnetic dipole into the hollow structure center and realize the ultrastrong Purcell enhancement of magnetic dipole emission, which can be more than 105. The designed structure can be applied to a variety of magneto-optical devices to greatly enhance Purcell effect in terahertz region.
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