Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems
Recently, several applications leveraging unconventional manipulation of electromagnetic radiation based on parity-time symmetry have been proposed in the literature. Typical examples include systems with unidirectional invisibility and asymmetric refraction. Such applications assume an inherent sys...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-02-01
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| Series: | Photonics |
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| Online Access: | https://www.mdpi.com/2304-6732/8/2/56 |
| _version_ | 1797396035492904960 |
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| author | Josip Lončar Josip Vuković Igor Krois Silvio Hrabar |
| author_facet | Josip Lončar Josip Vuković Igor Krois Silvio Hrabar |
| author_sort | Josip Lončar |
| collection | DOAJ |
| description | Recently, several applications leveraging unconventional manipulation of electromagnetic radiation based on parity-time symmetry have been proposed in the literature. Typical examples include systems with unidirectional invisibility and asymmetric refraction. Such applications assume an inherent system stability and no occurrence of unbounded signal growth or unwanted self-oscillations. Here, a general instability issue of parity-time-symmetric systems is investigated, with particular emphasis on a recently proposed system based on resistive metasurfaces. Explicit closed-form stability criterion is derived, crosschecked and verified by both time-domain transient simulations and the measurements on an experimental demonstrator operating in a lower radiofrequency range. Results of this study lead to the conclusion that any parity-time-symmetric system is necessarily marginally stable. Finally, it is shown that such a marginally stable system may easily become unstable if not designed carefully. |
| first_indexed | 2024-03-09T00:44:30Z |
| format | Article |
| id | doaj.art-38683dc51efb4a32800c381d2dc68cf5 |
| institution | Directory Open Access Journal |
| issn | 2304-6732 |
| language | English |
| last_indexed | 2024-03-09T00:44:30Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Photonics |
| spelling | doaj.art-38683dc51efb4a32800c381d2dc68cf52023-12-11T17:34:03ZengMDPI AGPhotonics2304-67322021-02-01825610.3390/photonics8020056Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic SystemsJosip Lončar0Josip Vuković1Igor Krois2Silvio Hrabar3Faculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, 10000 Zagreb, CroatiaFaculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, 10000 Zagreb, CroatiaFaculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, 10000 Zagreb, CroatiaFaculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, 10000 Zagreb, CroatiaRecently, several applications leveraging unconventional manipulation of electromagnetic radiation based on parity-time symmetry have been proposed in the literature. Typical examples include systems with unidirectional invisibility and asymmetric refraction. Such applications assume an inherent system stability and no occurrence of unbounded signal growth or unwanted self-oscillations. Here, a general instability issue of parity-time-symmetric systems is investigated, with particular emphasis on a recently proposed system based on resistive metasurfaces. Explicit closed-form stability criterion is derived, crosschecked and verified by both time-domain transient simulations and the measurements on an experimental demonstrator operating in a lower radiofrequency range. Results of this study lead to the conclusion that any parity-time-symmetric system is necessarily marginally stable. Finally, it is shown that such a marginally stable system may easily become unstable if not designed carefully.https://www.mdpi.com/2304-6732/8/2/56PT symmetrymetasurfacesstability analysisnegative-impedance converter |
| spellingShingle | Josip Lončar Josip Vuković Igor Krois Silvio Hrabar Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems Photonics PT symmetry metasurfaces stability analysis negative-impedance converter |
| title | Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems |
| title_full | Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems |
| title_fullStr | Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems |
| title_full_unstemmed | Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems |
| title_short | Stability Constraints on Practical Implementation of Parity-Time-Symmetric Electromagnetic Systems |
| title_sort | stability constraints on practical implementation of parity time symmetric electromagnetic systems |
| topic | PT symmetry metasurfaces stability analysis negative-impedance converter |
| url | https://www.mdpi.com/2304-6732/8/2/56 |
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