Highly Sensitive THz Gas-Sensor Based on the Guided Bloch Surface Wave Resonance in Polymeric Photonic Crystals

THz waves have interesting applications in refractive index sensing. A THz gas sensor based on the guided Bloch surface wave resonance (GBSWR) in a one-dimensional photonic crystal (1DPhC), which consists of periodic polycarbonate (PC) layers and polyvinylidene fluoride (PVDF) layers, has been proposed. Numerical results based on finite element method (FEM) show that the photonic band gap that confines Bloch surface waves (BSWs) lies in the regime of 11.54 to 21.43 THz, in which THz wave can transmit in both PC and PVDF with the ignored absorption. The calculated sensitivity of hazardous gas HCN in angle is found to be 118.6°/RIU (and the corresponding figure of merit (FOM) is 227) and the sensitivity in frequency is 4.7 THz/RIU (the corresponding FOM is 301.3). The proposed structure may also be used for monitoring hazardous gases which show absorption to the incident THz wave. Further results show that for N2O gas, the maximum sensitivity goes up to 644 (transmittance unit/ one unit of the imaginary part of the refractive index). The proposed design may find applications in the detection of dangerous gases.

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Bloch Surface Wave Resonance Based Sensors as an Alternative to Surface Plasmon Resonance Sensors

Sensors ◽

10.3390/s20185119 ◽

2020 ◽

Vol 20 (18) ◽

pp. 5119 ◽

Cited By ~ 1

Author(s):

Michal Gryga ◽

Dalibor Ciprian ◽

Petr Hlubina

Keyword(s):

Surface Plasmon Resonance ◽

Surface Wave ◽

Surface Plasmon ◽

Plasmon Resonance ◽

Moist Air ◽

Polarized Waves ◽

Wave Resonance ◽

Highly Sensitive ◽

Bloch Surface Wave ◽

Spr Effect

We report on a highly sensitive measurement of the relative humidity (RH) of moist air using both the surface plasmon resonance (SPR) and Bloch surface wave resonance (BSWR). Both resonances are resolved in the Kretschmann configuration when the wavelength interrogation method is utilized. The SPR is revealed for a multilayer plasmonic structure of SF10/Cr/Au, while the BSWR is resolved for a multilayer dielectric structure (MDS) comprising four bilayers of TiO2/SiO2 with a rough termination layer of TiO2. The SPR effect is manifested by a dip in the reflectance of a p-polarized wave, and a shift of the dip with the change in the RH, or equivalently with the change in the refractive index of moist air is revealed, giving a sensitivity in a range of 0.042–0.072 nm/%RH. The BSWR effect is manifested by a dip in the reflectance of the spectral interference of s- and p-polarized waves, which represents an effective approach in resolving the resonance with maximum depth. For the MDS under study, the BSWRs were resolved within two band gaps, and for moist air we obtained sensitivities of 0.021–0.038 nm/%RH and 0.046–0.065 nm/%RH, respectively. We also revealed that the SPR based RH measurement is with the figure of merit (FOM) up to 4.7 × 10−4 %RH−1, while BSWR based measurements have FOMs as high as 3.0 × 10−3 %RH−1 and 1.1 × 10−3 %RH−1, respectively. The obtained spectral interferometry based results demonstrate that the BSWR based sensor employing the available MDS has a similar sensitivity as the SPR based sensor, but outperforms it in the FOM. BSW based sensors employing dielectrics thus represent an effective alternative with a number of advantages, including better mechanical and chemical stability than metal films used in SPR sensing.

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Bloch surface wave resonance in photonic crystal fibers: towards ultra-wide range refractive index sensors

Optics Express ◽

10.1364/oe.27.008236 ◽

2019 ◽

Vol 27 (6) ◽

pp. 8236 ◽

Cited By ~ 8

Author(s):

Esteban Gonzalez-Valencia ◽

Rodrigo Acuna Herrera ◽

Pedro Torres

Keyword(s):

Refractive Index ◽

Photonic Crystal ◽

Surface Wave ◽

Photonic Crystal Fibers ◽

Wave Resonance ◽

Wide Range ◽

Bloch Surface Wave ◽

Refractive Index Sensors ◽

Crystal Fibers

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Theoretical Model for a Highly Sensitive Near Infrared Biosensor Based on Bloch Surface Wave with Dirac Semimetal

Biosensors ◽

10.3390/bios11100390 ◽

2021 ◽

Vol 11 (10) ◽

pp. 390

Author(s):

Qiwen Zheng ◽

Yamei Liu ◽

Wenguang Lu ◽

Xiaoyu Dai ◽

Haishan Tian ◽

...

Keyword(s):

Refractive Index ◽

Theoretical Model ◽

Surface Wave ◽

Near Infrared ◽

Structural Parameters ◽

Refractive Index Sensitivity ◽

Dirac Semimetal ◽

Highly Sensitive ◽

Bloch Surface Wave ◽

Index Sensitivity

In this work, we present a theoretical model of a near-infrared sensitive refractive index biosensor based on the truncate 1D photonic crystal (1D PC) structure with Dirac semimetal. This highly sensitive near-infrared biosensor originates from the sharp reflectance peak caused by the excitation of Bloch surface wave (BSW) at the interface between the Dirac semimetal and 1D PC. The sensitivity of the biosensor model is sensitive to the Fermi energy of Dirac semimetal, the thickness of the truncate layer and the refractive index of the sensing medium. By optimizing the structural parameters, the maximum refractive index sensitivity of the biosensor model can surpass 17.4 × 103/RIU, which achieves a certain competitiveness compared to conventional surface plasmon resonance (SPR) or BSW sensors. Considering that bulk materials are easier to handle than two-dimensional materials in manufacturing facilities, we judge that 3D Dirac semimetal and its related devices will provide a strong competitor and alternative to graphene-based devices.

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