Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide
Terahertz (THz) molecular fingerprint spectroscopy provides a powerful label-free tool for detecting trace-amount analytes. Introducing extra microstructures such as metasurfaces to confine the field energy is essential to improve the sensitivity. However, the area of analyte film on conventional en...
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| Format: | Article |
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MDPI AG
2024-12-01
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| Series: | Photonics |
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| Online Access: | https://www.mdpi.com/2304-6732/12/1/14 |
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| author | Lu Nie Xiangjun Li Dongzhe Chen Zihao Wang Dexian Yan |
| author_facet | Lu Nie Xiangjun Li Dongzhe Chen Zihao Wang Dexian Yan |
| author_sort | Lu Nie |
| collection | DOAJ |
| description | Terahertz (THz) molecular fingerprint spectroscopy provides a powerful label-free tool for detecting trace-amount analytes. Introducing extra microstructures such as metasurfaces to confine the field energy is essential to improve the sensitivity. However, the area of analyte film on conventional enhancing metasurfaces must be larger than the beam spot in a free-space measuring setup. Here, we propose a tunable defect cavity of one-dimensional photonic crystal in the combined coaxial waveguide (CCW) and enhance the broadband THz fingerprint of trace analytes on a much smaller area. The peaks of high Q resonances can form a wide absorption spectrum by changing the length of the rubber part of the coaxial waveguide. For the 0.2 µm α-lactose film sample in the frequency range of 0.48–0.58 THz, the absorption enhancement factor of 89.2 times based on the thickness can be achieved and the sample area is about 1/1700 of that in the free-space measurement with the 5 mm beam waist. We first introduce the coaxial waveguide in the terahertz absorption spectra enhancement. With our proposed structure the analyte volume is effectively reduced which is significant in the real application scenario. |
| format | Article |
| id | doaj-art-c8d3c38dc1704507a91f2e9a565a7c1e |
| institution | Kabale University |
| issn | 2304-6732 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | MDPI AG |
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| series | Photonics |
| spelling | doaj-art-c8d3c38dc1704507a91f2e9a565a7c1e2025-01-24T13:46:11ZengMDPI AGPhotonics2304-67322024-12-011211410.3390/photonics12010014Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial WaveguideLu Nie0Xiangjun Li1Dongzhe Chen2Zihao Wang3Dexian Yan4Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, China Jiliang University, Hangzhou 310018, ChinaKey Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, China Jiliang University, Hangzhou 310018, ChinaKey Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, China Jiliang University, Hangzhou 310018, ChinaKey Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, China Jiliang University, Hangzhou 310018, ChinaKey Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province, China Jiliang University, Hangzhou 310018, ChinaTerahertz (THz) molecular fingerprint spectroscopy provides a powerful label-free tool for detecting trace-amount analytes. Introducing extra microstructures such as metasurfaces to confine the field energy is essential to improve the sensitivity. However, the area of analyte film on conventional enhancing metasurfaces must be larger than the beam spot in a free-space measuring setup. Here, we propose a tunable defect cavity of one-dimensional photonic crystal in the combined coaxial waveguide (CCW) and enhance the broadband THz fingerprint of trace analytes on a much smaller area. The peaks of high Q resonances can form a wide absorption spectrum by changing the length of the rubber part of the coaxial waveguide. For the 0.2 µm α-lactose film sample in the frequency range of 0.48–0.58 THz, the absorption enhancement factor of 89.2 times based on the thickness can be achieved and the sample area is about 1/1700 of that in the free-space measurement with the 5 mm beam waist. We first introduce the coaxial waveguide in the terahertz absorption spectra enhancement. With our proposed structure the analyte volume is effectively reduced which is significant in the real application scenario.https://www.mdpi.com/2304-6732/12/1/14terahertz (THz) molecular fingerprintone-dimensional photonic crystal (1D-PC)combined coaxial waveguide (CCW)THz absorption spectra |
| spellingShingle | Lu Nie Xiangjun Li Dongzhe Chen Zihao Wang Dexian Yan Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide Photonics terahertz (THz) molecular fingerprint one-dimensional photonic crystal (1D-PC) combined coaxial waveguide (CCW) THz absorption spectra |
| title | Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide |
| title_full | Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide |
| title_fullStr | Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide |
| title_full_unstemmed | Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide |
| title_short | Enhancing Terahertz Absorption Spectrum Based on a Tunable Defect Cavity of One-Dimensional Photonic Crystal in the Combined Coaxial Waveguide |
| title_sort | enhancing terahertz absorption spectrum based on a tunable defect cavity of one dimensional photonic crystal in the combined coaxial waveguide |
| topic | terahertz (THz) molecular fingerprint one-dimensional photonic crystal (1D-PC) combined coaxial waveguide (CCW) THz absorption spectra |
| url | https://www.mdpi.com/2304-6732/12/1/14 |
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