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| Main Authors: | , , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2404.17281 |
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| _version_ | 1866917651507314688 |
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| author | Wang, Jun Liu, Jie Hu, Peng Jiang, Qiao Han, Dezhuan |
| author_facet | Wang, Jun Liu, Jie Hu, Peng Jiang, Qiao Han, Dezhuan |
| contents | A Dirac point in the Hermitian photonic system will split into a pair of exceptional points (EPs) or even spawn a ring of EPs if non-Hermiticity is involved. Here, we present a new type of non-Hermitian Dirac point which is situated in the complex plane of eigenfrequency. When there is differential loss, the Dirac point exhibits a dual behavior: it not only splits into a pair of EPs with opposite chirality in the band structure but also induces a pair of circularly polarized states (C points) with opposite handedness in the far-field radiation. Furthermore, breaking the corresponding mirror symmetries enables independent control of these Dirac-point induced C points, facilitating the merging of two C points and generation of unidirectional guided resonances. Our results demonstrate an explicit relation between the band singularities and polarization singularities, and provide a new mechanism to generate unidirectional emission, which can be useful in the band engineering and polarization manipulation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_17281 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Topological polarization singularities induced by the non-Hermitian Dirac points Wang, Jun Liu, Jie Hu, Peng Jiang, Qiao Han, Dezhuan Optics A Dirac point in the Hermitian photonic system will split into a pair of exceptional points (EPs) or even spawn a ring of EPs if non-Hermiticity is involved. Here, we present a new type of non-Hermitian Dirac point which is situated in the complex plane of eigenfrequency. When there is differential loss, the Dirac point exhibits a dual behavior: it not only splits into a pair of EPs with opposite chirality in the band structure but also induces a pair of circularly polarized states (C points) with opposite handedness in the far-field radiation. Furthermore, breaking the corresponding mirror symmetries enables independent control of these Dirac-point induced C points, facilitating the merging of two C points and generation of unidirectional guided resonances. Our results demonstrate an explicit relation between the band singularities and polarization singularities, and provide a new mechanism to generate unidirectional emission, which can be useful in the band engineering and polarization manipulation. |
| title | Topological polarization singularities induced by the non-Hermitian Dirac points |
| topic | Optics |
| url | https://arxiv.org/abs/2404.17281 |