Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure

Simultaneous realization of high quality factor (Q), sensitivity, and figure of merit (FOM) play a pivotal role in building the THz sensor. For such purpose, we propose an all-polymeric Bloch surface wave (BSW) structure that supports a bright BSW mode and a dark surface Fano state that is embedded...

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Autores principales:	Zhang Chi, Liu Qiang, Peng Xiao, Ouyang Zhengbiao, Shen Suling
Formato:	article
Lenguaje:	EN
Publicado:	De Gruyter 2021
Materias:	bloch surface wave fano resonance high q factor thz sensor Physics QC1-999
Acceso en línea:	https://doaj.org/article/ffb15224837f4e4a9cb900299a5e36e8
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spelling	oai:doaj.org-article:ffb15224837f4e4a9cb900299a5e36e82021-12-05T14:10:56ZSensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure2192-861410.1515/nanoph-2021-0339https://doaj.org/article/ffb15224837f4e4a9cb900299a5e36e82021-10-01T00:00:00Zhttps://doi.org/10.1515/nanoph-2021-0339https://doaj.org/toc/2192-8614Simultaneous realization of high quality factor (Q), sensitivity, and figure of merit (FOM) play a pivotal role in building the THz sensor. For such purpose, we propose an all-polymeric Bloch surface wave (BSW) structure that supports a bright BSW mode and a dark surface Fano state that is embedded in the continuum, both of which coupled to the same radiation channels. The existence of the sharp dip with a maximum depth of Fano line could be interpreted with the physics of Friedrich–Wintgen bound states in the continuum (FW-BICs), because of the destructive interference between bright BSW and dark surface Fano modes. A strong angular- and frequency-dependent Q was found. Related influential factors to Q value may also include an asymmetric arrangement of top and grating layers, together with the weak coupling provided by photonic crystals. One numerically optimized design shows a quality factor Q of the Fano mode as 23,670, which is almost two orders higher than that in conventional metallic-metamaterial-based designs. The optimized sensitivity can numerically reach 4.34 THz/RIU in the frequency domain, which is one order higher than that reported in all-dielectric metasurfaces. We infer the high sensitivity is related to the phase-matching condition provided by near-subwavelength gratings. The associated FOM can reach 8857/RIU. Besides, the proposed design also numerically demonstrates high sensitivity in the angular domain ∼125.5°/RIU. Considering it poses no specific requirement for materials that own high contrast of permittivity in the THz regime, large interfacing area, the mechanical and chemical robustness offered by polymers and low cost in fabrication, such all-polymeric BSW structure that supports novel Fano resonance in THz window may give access to rich applications in hazardous gas detection and label-free bio-sensing.Zhang ChiLiu QiangPeng XiaoOuyang ZhengbiaoShen SulingDe Gruyterarticlebloch surface wavefano resonancehigh q factorthz sensorPhysicsQC1-999ENNanophotonics, Vol 10, Iss 15, Pp 3879-3888 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	bloch surface wave fano resonance high q factor thz sensor Physics QC1-999
spellingShingle	bloch surface wave fano resonance high q factor thz sensor Physics QC1-999 Zhang Chi Liu Qiang Peng Xiao Ouyang Zhengbiao Shen Suling Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
description	Simultaneous realization of high quality factor (Q), sensitivity, and figure of merit (FOM) play a pivotal role in building the THz sensor. For such purpose, we propose an all-polymeric Bloch surface wave (BSW) structure that supports a bright BSW mode and a dark surface Fano state that is embedded in the continuum, both of which coupled to the same radiation channels. The existence of the sharp dip with a maximum depth of Fano line could be interpreted with the physics of Friedrich–Wintgen bound states in the continuum (FW-BICs), because of the destructive interference between bright BSW and dark surface Fano modes. A strong angular- and frequency-dependent Q was found. Related influential factors to Q value may also include an asymmetric arrangement of top and grating layers, together with the weak coupling provided by photonic crystals. One numerically optimized design shows a quality factor Q of the Fano mode as 23,670, which is almost two orders higher than that in conventional metallic-metamaterial-based designs. The optimized sensitivity can numerically reach 4.34 THz/RIU in the frequency domain, which is one order higher than that reported in all-dielectric metasurfaces. We infer the high sensitivity is related to the phase-matching condition provided by near-subwavelength gratings. The associated FOM can reach 8857/RIU. Besides, the proposed design also numerically demonstrates high sensitivity in the angular domain ∼125.5°/RIU. Considering it poses no specific requirement for materials that own high contrast of permittivity in the THz regime, large interfacing area, the mechanical and chemical robustness offered by polymers and low cost in fabrication, such all-polymeric BSW structure that supports novel Fano resonance in THz window may give access to rich applications in hazardous gas detection and label-free bio-sensing.
format	article
author	Zhang Chi Liu Qiang Peng Xiao Ouyang Zhengbiao Shen Suling
author_facet	Zhang Chi Liu Qiang Peng Xiao Ouyang Zhengbiao Shen Suling
author_sort	Zhang Chi
title	Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
title_short	Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
title_full	Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
title_fullStr	Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
title_full_unstemmed	Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure
title_sort	sensitive thz sensing based on fano resonance in all-polymeric bloch surface wave structure
publisher	De Gruyter
publishDate	2021
url	https://doaj.org/article/ffb15224837f4e4a9cb900299a5e36e8
work_keys_str_mv	AT zhangchi sensitivethzsensingbasedonfanoresonanceinallpolymericblochsurfacewavestructure AT liuqiang sensitivethzsensingbasedonfanoresonanceinallpolymericblochsurfacewavestructure AT pengxiao sensitivethzsensingbasedonfanoresonanceinallpolymericblochsurfacewavestructure AT ouyangzhengbiao sensitivethzsensingbasedonfanoresonanceinallpolymericblochsurfacewavestructure AT shensuling sensitivethzsensingbasedonfanoresonanceinallpolymericblochsurfacewavestructure
_version_	1718371580468264960

Sensitive THz sensing based on Fano resonance in all-polymeric Bloch surface wave structure

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