Progress on Optical Fiber Biochemical Sensors Based on Graphene

Abstract

Graphene, a novel form of the hexagonal honeycomb two-dimensional carbon-based structural material with a zero-band gap and ultra-high specific surface area, has unique optoelectronic capabilities, promising a suitable basis for its application in the field of optical fiber sensing. Graphene optical fiber sensing has also been a hotspot in cross-research in biology, materials, medicine, and micro-nano devices in recent years, owing to prospective benefits, such as high sensitivity, small size, and strong anti-electromagnetic interference capability and so on. Here, the progress of optical fiber biochemical sensors based on graphene is reviewed. The fabrication of graphene materials and the sensing mechanism of the graphene-based optical fiber sensor are described. The typical research works of graphene-based optical fiber biochemical sensor, such as long-period fiber grating, Bragg fiber grating, no-core fiber and photonic crystal fiber are introduced, respectively. Finally, prospects for graphene-based optical fiber biochemical sensing technology will also be covered, which will provide an important reference for the development of graphene-based optical fiber biochemical sensors.

Keywords: biochemical sensor; evanescent wave; fiber grating; graphene; optical fiber; photonic crystal fiber.

Figure 1

Synthesis process diagram of four different methods for preparing graphene (a) mechanical exfoliation method. (b) Oxidation-reduction method. (c) Chemical vapor deposition method. (d) Epitaxial growth method.

Figure 2

(a) The structure of graphene. (b) Experimental and calculated angular dependence of the ratio of optical reflectance of TM wave to monolayer TE wave. (c) Extinction ratio at different wavelengths in s- and p-polarized pass situation. (d) Variation of GQDs excitation wavelength. (e) Optical conductivity of the monolayer graphene up to ultraviolet frequency. (f) SPR-sensing characteristics. Reproduced from [67,77,78] with permission of the Elsevier.

Figure 3

SPR-sensing mechanism of D-type photonic crystal fiber (PCF) sensor. (a) Graphene Brillouin zone. (b) Linear dispersion diagram of the band structure of monolayer graphene. (c) Schematic diagram of graphene-Au-sensing mechanism. Reproduced from [81] with permission of the Multidisciplinary Digital Publishing Institute.

Figure 4

Diagrams of biochemical sensors for detecting important substances in different fields.

Figure 5

(a) Schematic diagram of optical fiber biosensor comprising the dLPG coated with the graphene oxide-linking layer. (b) The Raman spectrum of GO-coated fiber compared with bare fiber. (c) Transmission spectra of bare dLPG measured in different sucrose concentrations. (d) Dual-peak wavelength separation against SRI. (e) Transmission spectra of bare dLPG measured in different sucrose concentrations. (f) Spectra evolution of non-coated, GO-coated, and IgG-immobilized dLPG. Reproduced from [93] with permission of Elsevier.

Figure 6

(a) The structure diagram of the graphene-based LPFG SPR sensor. (b) The sectional diagram of the graphene-based LPFG SPR sensor. (c) Transmission spectra of LFBG sensor. (d) Transmission spectra of graphene-based LFBG SPR sensor in different concentrations of methane gas. (e) Transmission spectra of Ag-coated LFBG SPR sensor. (f) Resonance wavelength shift versus concentration of methane. Reproduced from [94] with permission of the Multidisciplinary Digital Publishing Institute.

Figure 7

(a) Schematic illustration of the NO₂ gas-sensing mechanism on the RGO-coated eFBG. (b) SEM image of the eFBG sensor showing uniformly coated RGO in the FBG region. (c) EDAX spectra recorded from RGO flakes (designated by the black-colored rectangular box in Figure 6a) coated on the eFBG sensor surface. (d) Raman spectra of GO flakes (coated on eFBG sensor), before and after the reduction. Reproduced from [99] with permission of Elsevier.

Figure 8

(a) Schematic diagram of the GO-sensitized SNS sensor. (b) Flow chart of GO production (c) SEM image of GO-coated fiber sensor. (d) Micrograph of solder joint. (e) Sensitivity and linearity at different RI wavelengths (simulated and experimental). (f) The relationship between the characteristic wavelength and the refractive index of the coated and uncoated GO. Reproduced from [101] with permission of the Multidisciplinary Digital Publishing Institute.

Figure 9

(a) The schematic diagram of MMF-PCF-MMF (multimode fiber-photonic crystal fiber- multimode fiber) sensor. (b) The end-face micrograph of PCF. (c) GO and SPA modified process for IgG immunoassay. (d) Goat anti-human IgG immobilized on the sensor surface. Error bars represent the standard deviation of three independent experiments. Reproduced from [107] with permission of Elsevier.