Passive nonreciprocal transmission and optical bistability based on polarization-independent bound states in the continuum

Autor: Chen Shiwen, Zeng Yixuan, Li Zhongfu, Mao Yu, Dai Xiaoyu, Xiang Yuanjiang
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Nanophotonics, Vol 12, Iss 18, Pp 3613-3621 (2023)
Druh dokumentu: article
ISSN: 2192-8614
DOI: 10.1515/nanoph-2023-0319
Popis: Free-space nonreciprocal transmission is a crucial aspect of modern optics devices. The implementation of nonreciprocal optical devices through optical nonlinearity has been demonstrated. However, due to the weak nonlinearity of traditional materials, most self-biased nonreciprocal devices are heavily dependent on the high Q strong resonances. In general, these resonances are frequently polarization sensitive. In this work, we propose ultrathin optical metasurface embedding Kerr nonlinearities to achieve nonreciprocal transmission and optical bistability for free-space propagation based on symmetry-protected bound states in the continuum (BICs). Since the structure of the metasurface retains C4ν symmetry, the symmetry-protected BIC is polarization-independent. It is also shown that the nonreciprocal intensity range could be largely tuned by the structure parameters. The demonstrated devices merge the field of nonreciprocity with ultrathin metasurface technologies making this design an exciting prospect for an optical switch, routing, and isolator with optimal performance.
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