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Vaňko M, Glesk I, Müllerová J, Dubovan J, Dado M. Design, Optimization, and Experimental Evaluation of Slow Light Generated by π-Phase-Shifted Fiber Bragg Grating for Use in Sensing Applications. SENSORS (BASEL, SWITZERLAND) 2024; 24:340. [PMID: 38257433 PMCID: PMC10819782 DOI: 10.3390/s24020340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/24/2024]
Abstract
This paper describes design, theoretical analysis, and experimental evaluation of a π-Phase-Shifted Fiber Bragg Grating (π-PSFBG) inscribed in the standard telecom fiber for slow light generation. At first, the grating was designed for its use in the reflection mode with a central wavelength of 1552 nm and a pass band width of less than 100 pm. The impact of fabrication imperfections was experimentally investigated and compared to model predictions. The optical spectra obtained experimentally show that the spectral region used for slow light generation is narrower (less than 10 pm), thus allowing for too-low levels of slow light optical-output power. In the next step, the optimization of the grating design was conducted to account for fabrication errors, to improve the grating's spectral behavior and its temporal performance, and to widen the spectral interval for slow light generation in the grating's transmission mode. The targeted central wavelength was 1553 nm. The π-PSFBG was then commercially fabricated, and the achieved parameters were experimentally investigated. For the region of (1551-1554) nm, a 15-fold increase in the grating's pass band width was achieved. We have shown that a pair of retarded optical pulses were generated. The measured group delay was found to be ~10.5 ps (compared to 19 ps predicted by the model). The π-PSFBG operating in its transmission mode has the potential to operate as tunable delay line for applications in RF photonics, ultra-fast signal processing, and optical communications, where tunable high precision delay lines are highly desirable. The π-PSFBG can be designed and used for the generation of variable group delays from tens to hundreds of ps, depending on application needs.
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Affiliation(s)
- Matúš Vaňko
- Department of Multimedia and Information-Communication Technologies, Faculty of Electrical Engineering and Information Technology, University of Žilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia; (M.V.); (J.D.); (M.D.)
| | - Ivan Glesk
- Electronic and Electrical Engineering Department, University of Strathclyde, 204 George Street, Glasgow G1 1XW, UK
| | - Jarmila Müllerová
- Institute of Aurel Stodola, Faculty of Electrical Engineering and Information Technology, University of Žilina, Komenského 843, 031 01 Liptovský Mikuláš, Slovakia;
| | - Jozef Dubovan
- Department of Multimedia and Information-Communication Technologies, Faculty of Electrical Engineering and Information Technology, University of Žilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia; (M.V.); (J.D.); (M.D.)
| | - Milan Dado
- Department of Multimedia and Information-Communication Technologies, Faculty of Electrical Engineering and Information Technology, University of Žilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia; (M.V.); (J.D.); (M.D.)
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Meng F, Cao L, Karalis A, Gu H, Thomson MD, Roskos HG. Strong coupling of plasmonic bright and dark modes with two eigenmodes of a photonic crystal cavity. OPTICS EXPRESS 2023; 31:39624-39637. [PMID: 38041279 DOI: 10.1364/oe.500646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 09/30/2023] [Indexed: 12/03/2023]
Abstract
Dark modes represent a class of forbidden transitions or transitions with weak dipole moments between energy states. Due to their low transition probability, it is difficult to realize their interaction with light, let alone achieve the strong interaction of the modes with the photons in a cavity. However, by mutual coupling with a bright mode, the strong interaction of dark modes with photons is possible. This type of mediated interaction is widely investigated in the metamaterials community and is known under the term electromagnetically induced transparency (EIT). Here, we report strong coupling between a plasmonic dark mode of an EIT-like metamaterial with the photons of a 1D photonic crystal cavity in the terahertz frequency range. The coupling between the dark mode and the cavity photons is mediated by a plasmonic bright mode, which is proven by the observation of a frequency splitting which depends on the strength of the inductive interaction between the plasmon bright and dark modes of the EIT-like metamaterial. In addition, since the plasmonic dark mode strongly couples with the cavity dark mode, we observes four polariton modes. The frequency splitting by interaction of the four modes (plasmonic bright and dark mode and the two eigenmodes of the photonic cavity) can be reproduced in the framework of a model of four coupled harmonic oscillators.
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Abdelraouf OAM, Wang Z, Liu H, Dong Z, Wang Q, Ye M, Wang XR, Wang QJ, Liu H. Recent Advances in Tunable Metasurfaces: Materials, Design, and Applications. ACS NANO 2022; 16:13339-13369. [PMID: 35976219 DOI: 10.1021/acsnano.2c04628] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Metasurfaces, a two-dimensional (2D) form of metamaterials constituted by planar meta-atoms, exhibit exotic abilities to tailor electromagnetic (EM) waves freely. Over the past decade, tremendous efforts have been made to develop various active materials and incorporate them into functional devices for practical applications, pushing the research of tunable metasurfaces to the forefront of nanophotonics. Those active materials include phase change materials (PCMs), semiconductors, transparent conducting oxides (TCOs), ferroelectrics, liquid crystals (LCs), atomically thin material, etc., and enable intriguing performances such as fast switching speed, large modulation depth, ultracompactness, and significant contrast of optical properties under external stimuli. Integration of such materials offers substantial tunability to the conventional passive nanophotonic platforms. Tunable metasurfaces with multifunctionalities triggered by various external stimuli bring in rich degrees of freedom in terms of material choices and device designs to dynamically manipulate and control EM waves on demand. This field has recently flourished with the burgeoning development of physics and design methodologies, particularly those assisted by the emerging machine learning (ML) algorithms. This review outlines recent advances in tunable metasurfaces in terms of the active materials and tuning mechanisms, design methodologies, and practical applications. We conclude this review paper by providing future perspectives in this vibrant and fast-growing research field.
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Affiliation(s)
- Omar A M Abdelraouf
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Ziyu Wang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Hailong Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Zhaogang Dong
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Qian Wang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
| | - Ming Ye
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Xiao Renshaw Wang
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Qi Jie Wang
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Hong Liu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634, Singapore
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