Abstract

A compact fiber-optic Fabry-Perot interferometric (FFPI) volatile organic compounds (VOCs) sensor is fabricated based on a single mode fiber (SMF) and a polymethyl methacrylate (PMMA) film. The VOCs induce the swelling effect and refractive index changes of PMMA film. The swelling of PMMA film affects the cavity length of Fabry-Perot interferometer resulting in shift of resonant dip, while the change in refractive index influences reflection resulting in change of extinction ratio (ER). The sensitivities of 2.7 pm/ppm for ethanol and 2.17 pm/ppm for acetone are achieved. Moreover, this sensor is insensitive to the inorganic gases. In addition, it has the advantages of ease of fabrication and high sensitivity to VOCs.

© 2017 Optical Society of America

1. Introduction

Volatile organic compounds (VOCs) are a very common and vitally important substance. They are widely applied in various fields such as chemical industry, medical and health, food processing and industrial safety production. There is a great demand for the measurement of VOCs with high sensitivity and accuracy, such as ethanol and acetone. In recent years, many one-dimensional (1D) nanostructural materials, such as nanotubes [1, 2], nanowires [3, 4], nanorods [5, 6] and nanoparticles [7, 8] have been synthesized and used to fabricate ethanol and acetone gas sensors. However, these approaches have some limitations, the fabrication of nanostructural materials needs various complicated physical and chemical process, expensive apparatus and rigorous condition. It is also difficult to use the electrical sensors to detect the flammable and explosive gases such as ethanol and acetone. Therefore, it is of great importance to develop a sensor to detect these gases with high sensitivity, intrinsic safety and low cost.

Fiber-optic sensors can offer many advantages, such as light-weight, wholly passive, resistance to electromagnetic interference, and have already been applied for numerous sensing applications. The related fiber-optic sensors include fiber Bragg grating (FBG) [9–11], microfiber [12–15], photonic crystal fiber [16–18], Mach-Zehnder interferometer [19, 20] and Fabry-Perot interferometer [21–23]. Recently, increasing attention has been paid to combine gas sensitive materials with fiber-optic microstructures for various gas sensing, such as those based on metal oxide [24], grahene [25–28], catalysts [29] and polymer [30,31].

In this paper, we proposed a fiber-optic Fabry-Perot interferometric sensor based on a PMMA film with a thickness about 300 nm which shows a good sensitivity and selectivity for VOCs sensing. The Fabry-Perot cavity is formed by a fiber end and a PMMA film which coated at the tip of a glass tube. The PMMA exhibits a swelling effect and a refractive index change [32–34] when adsorbing the VOC molecules. The swelling of PMMA film affects the cavity length of Fabry-Perot interferometer resulting in shift of resonant dip, while the change in refractive index influences reflection and thus it’s ER. By monitoring the variation of resonant dip and ER, we can detect the concentration of the VOCs. In this experiment, the inorganic gases of ammonia (NH3), carbonic oxide (CO) and hydrogen (H2) are also used for sensing to demonstrate the selectivity of this VOCs sensor.

2. Sensing principle and fabrication of FFPI sensor

The schematic diagram of the FFPI sensor is shown in Fig. 1(a). The Fabry-Perot cavity consists of two reflective surfaces, they are, the end surface of SMF and PMMA film. In this structure, the reflection coefficient of SMF end surface is calculated to be approximately 3.6% based on the Fresnel reflection equation R = [(n1-n2)/(n1 + n2)]2 where n1≈1.47 is the refractive index of SMF core and n2≈1 is the refractive index of air. According to the two-beam interference, the maximum ER can be obtained when the intensity of the two beams are equal. Due to there is a divergence angle when the light is emitting from the end surface of SMF, the effective reflection coefficient of the PMMA film can be controlled by adjusting the distance between the fiber end and the PMMA film. Here, an optimized distance about 114 μm is gained to obtain the maximum ER. The reflective interference spectrum from the Fabry-Perot interferometer is shown in Fig. 1(b). The ER is ~33.6 dB, which is among the highest of FFPIs [35, 36].

 figure: Fig. 1

Fig. 1 (A) The schematic diagram of the FFPI sensor. (B) The reflective interference spectrum of the FFPI sensor.

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The reflective spectrum of the sensor can be expressed as

I(λ)=IFiber(λ)+IFilm(λ)+2IFiber(λ)IFilm(λ)cos(2πOPDλ).
Here, IFiber (λ) is the reflective intensity of the fiber end and IFilm (λ) is the reflective intensity of the PMMA film, both of which are only slightly dependent on the incident wavelength. OPD = 2l is the optical path difference, and l is the length of cavity. The minimum intensity of the interference occurs at the point λmin when OPD = mλ + λ/2, where m is integer. When the VOCs molecules are absorbed into PMMA film, the PMMA film will expand to increase the OPD resulting in the resonant dip λm shifts to a longer wavelength based on the Eq. (1). Meanwhile, the ER of the interference fringe can be written as
ER=10lgImaxImin=10lgIFiber(λ)+IFilm(λ)+2IFiber(λ)IFilm(λ)IFiber(λ)+IFilm(λ)2IFiber(λ)IFilm(λ).
Initially, IFiber (λ) and IFilm (λ) are modulated almost equal to acquire the largest ER. When the VOC molecules are absorbed into PMMA film, the refractive index of PMMA film will increase. And the IFilm (λ) will increase resulting in the ER becomes smaller based on the Eq. (2). By measuring the shifts of resonant dip and the changes of ER, the external VOC concentrations can be determined.

Figure 2 shows the fabrication process of the FFPI sensor. A mixed solution was prepared by putting the PMMA powder into ethyl lactate with a mass ratio of 4:100 and stirred by a magnetic stirrer for 48 hours in order to make PMMA dissolved into ethyl lactate completely. Then, the mixed solution was transferred onto a Cu foil and spin-coated by spin coater with a rotation speed of 5000 r/min for 30 seconds. The coated Cu foil was put onto a heating stage with the temperature of 150 °C to evaporate the ethyl lactate. Subsequently, the underlying Cu foil was etched by immersing it into a ferric chloride (FeCl3) solution. The PMMA film was washed in deionized water several times and then transferred onto the end surface of glass tube. Finally, a cleaved single mode fiber (SMF) was inserted into the glass tube and fixed by a UV glue to form a Fabry-Perot cavity.

 figure: Fig. 2

Fig. 2 The fabrication process of the FFPI sensor.

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3. Gas sensing experiments

In our experiment, the gas sensing responses of the sensor were tested in a constant-temperature environment. The experimental setup is shown in Fig. 3. A wavelength-swept laser with a wide tunable range was used as the light source (81960A, Agilent, USA). The reflected light from the sensor was collected and analyzed by a power detected-based optical spectrum analyzer (OSA, N744A, Agilent, USA). The FFPI sensor was placed in a gas chamber. The outlet of the gas chamber was connected with the external environment. So the pressure inside the gas chamber was equal to the atmospheric pressure. Firstly, the dry N2 gas was injected into chamber to exhaust the air and water vapor inside. Ethanol and acetone gases were used as examples of VOCs in the sensing experiments. The gas concentrations were obtained by evaporating the corresponding liquid in a container of a fixed volume.

 figure: Fig. 3

Fig. 3 The experimental setup for gas sensing.

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The concentrations of ethanol and acetone were controlled between 0 and 1800 ppm with a step of 300 ppm. The reflection spectrum of the sensor shifts to the longer wavelength by 0.82 nm, 1.6 nm, 2.42 nm, 3.21 nm, 3.92 nm and 4.72 nm with the ethanol gas concentrations of 300, 600, 900, 1200, 1500, 1800 ppm respectively as shown in Fig. 4(a). Wavelength shifts of 0.68 nm, 1.31 nm, 1.95 nm, 2.53 nm, 3.06 nm and 3.74 nm were obtained with acetone gas concentrations of 300, 600, 900, 1200, 1500, 1800 ppm respectively as shown in Fig. 4(b). According to the interference theory of Fabry-Perot, there is a formula of λ = 2nL/(m + 1/2). Here, m is an integer, λ is the wavelength of resonant dip, n is the refractive index of cavity, and L is the length of cavity. The resonant dip λ shifts to longer wavelength as the gas concentration increases, indicating the swelling of PMMA film increases the length of interference cavity. Meanwhile, a significant ER change of the interference fringes can also be observed. For ethanol, the ER decreased by 3.1 dB, 7.34 dB, 10.22 dB, 12.71 dB, 14.28 dB and 14.95 dB, respectively. For acetone, the decreases of ER were 3.32 dB, 7.31 dB, 9.15 dB, 11.8 dB, 13.95 dB and 15.36 dB, respectively. The decrease of ER and the increase of maximum intensity λmax indicated the refractive index of PMMA film increased, resulting in the increase of reflected light intensity from the PMMA film.

 figure: Fig. 4

Fig. 4 The experimental results of FFPI sensor for (A) ethanol, (B) acetone, (C) NH3, (D) CO and (E)H2 gas sensing.

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To investigate the selectivity of the sensor, the inorganic gases of NH3, CO and H2 were detected at the same concentrations, as shown in Figs. 4(c)-4(e). The interference spectrum is enlarged and shown as a function of the gas concentration increases. The reflection spectrum of the sensor shifts to longer wavelength are 0.25 nm, 0.1 nm and 0.009 nm for NH3, CO and H2 with the concentration of 1800 ppm are shown in Figs. 4(c)-4(e), respectively. These experimental results demonstrate the low sensitivity to these gases, indicating that this sensor has excellent selectivity to acetone and ethanol. This selective response of PMMA film to organic molecules can be explained by following mechanism [37]. The PMMA reacts with most organics. They all have the same atomic bond structure of –CH2C–. The interaction of PMMA and VOC molecules was physical reaction instead of chemical reaction. When the VOC molecules diffused into the relatively large molecular gap of PMMA, the PMMA molecules were separated from each other resulting in the swelling effect. Since NH3, CO and H2 gases are not VOCs, they were difficult to diffuse into PMMA to induce the swelling effect.

The linear fitting relationship between resonant dip shift and gas concentration is shown in Fig. 5(a). The curve fitting relationship between ER change and gas concentration is shown in Fig. 5(b). It is indicated that resonant dip shift of sensor has a good linear response for ethanol and acetone gas sensing. Because of the refractive index change tended to be saturated when more and more gas molecules were absorbed into PMMA film. So the ER change tended to be saturated, the ER change is not linear when the gas concentration is up to 900 ppm. The swelling effect has a bigger dynamic range than the refractive index change of PMMA film indicates that this FFPI sensor could work over a wide range by measuring the resonant dip shift. The ER change has a sensitivity of 0.011 dB/ppm and 0.01 dB/ppm for ethanol and acetone sensing, respectively. Also, the resonant dip shift has a sensitivity of 2.7 pm/ppm and 2.17 pm/ppm and the minimum concentration level of this sensor is ∼0.74 ppm and 0.93 ppm for ethanol and acetone sensing, mainly limited by the resolution of 2 pm of the optical spectrum analyzer. Figure 5(c) presents the temporal recoverability of the FFPI sensor by cyclically exposing the sensor in ethanol and acetone gas environment. It is demonstrated that this sensor has good repeatability.

 figure: Fig. 5

Fig. 5 (A) Dip shift and (B) ER change of the FFPI sensor as a function of the gas concentration increase. (C) The recoverability of the FFPI sensor.

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4. Conclusion

In conclusion, a compact fiber-optic Fabry-Perot interferometric sensor based on PMMA film is proposed and experimentally demonstrated. This sensor shows the characteristics of highly sensitive and selective detection for VOCs concentration at room temperature. Moreover, the sensor shows good repeatability for VOCs sensing. The advantages of high sensitivity and selectivity for VOCs, easy to be fabricated and low cost make this sensor a big promising method for VOCs sensing applications. In our further work, we can combine fiber-optic Fabry-Perot interferometric with different high sensitive film such as graphene based functional materials and metal doped two-dimensional thin films, which can greatly promote its applications for different gas sensing.

Funding

National Natural Science Foundation of China (NSFC) (61290312, 61475032, and 61575039); Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT, IRT1218); 111 Project (B14039).

References and links

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3. Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004). [CrossRef]  

4. C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016). [CrossRef]  

5. L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012). [CrossRef]  

6. H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010). [CrossRef]  

7. S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016). [CrossRef]  

8. Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015). [CrossRef]  

9. Y. J. Rao, “In-fibre Bragg grating sensors,” Meas. Sci. Technol. 8(4), 355–375 (1997). [CrossRef]  

10. Y. J. Rao, “Recent progress in applications of in-fibre Bragg grating sensors,” Opt. Lasers Eng. 31(4), 297–324 (1999). [CrossRef]  

11. B. Gu, M. Yin, A. P. Zhang, J. Qian, and S. He, “Optical fiber relative humidity sensor based on FBG incorporated thin-core fiber modal interferometer,” Opt. Express 19(5), 4140–4146 (2011). [CrossRef]   [PubMed]  

12. Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014). [CrossRef]   [PubMed]  

13. J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014). [CrossRef]   [PubMed]  

14. J. L. Kou, J. Feng, Q. J. Wang, F. Xu, and Y. Q. Lu, “Microfiber-probe-based ultrasmall interferometric sensor,” Opt. Lett. 35(13), 2308–2310 (2010). [CrossRef]   [PubMed]  

15. W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012). [CrossRef]  

16. D. K. C. Wu, B. T. Kuhlmey, and B. J. Eggleton, “Ultrasensitive photonic crystal fiber refractive index sensor,” Opt. Lett. 34(3), 322–324 (2009). [CrossRef]   [PubMed]  

17. X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010). [CrossRef]  

18. Y. Yu, X. Li, X. Hong, Y. Deng, K. Song, Y. Geng, H. Wei, and W. Tong, “Some features of the photonic crystal fiber temperature sensor with liquid ethanol filling,” Opt. Express 18(15), 15383–15388 (2010). [CrossRef]   [PubMed]  

19. B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014). [CrossRef]  

20. G. L. Yin, S. Q. Lou, and H. Zou, “Refractive index sensor with asymmetrical fiber Mach–Zehnder interferometer based on concatenating single-mode abrupt taper and core-offset section,” Opt. Laser Technol. 45, 294–300 (2013). [CrossRef]  

21. Y. J. Rao, “Recent progress in fiber-optic extrinsic Fabry-Perot interferometric sensors,” Opt. Fiber Technol. 12(3), 227–237 (2006). [CrossRef]  

22. Y. J. Rao, M. Deng, D. W. Duan, X. C. Yang, T. Zhu, and G. H. Cheng, “Micro Fabry-Perot interferometers in silica fibers machined by femtosecond laser,” Opt. Express 15(21), 14123–14128 (2007). [CrossRef]   [PubMed]  

23. P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014). [CrossRef]  

24. Z. L. Poole, P. Ohodnicki, R. Chen, Y. Lin, and K. P. Chen, “Engineering metal oxide nanostructures for the fiber optic sensor platform,” Opt. Express 22(3), 2665–2674 (2014). [CrossRef]   [PubMed]  

25. B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014). [CrossRef]   [PubMed]  

26. H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011). [CrossRef]  

27. C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016). [CrossRef]  

28. S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016). [CrossRef]  

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33. U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002). [CrossRef]  

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35. Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010). [CrossRef]  

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References

  • View by:

  1. W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
    [Crossref]
  2. S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
    [Crossref]
  3. Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
    [Crossref]
  4. C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016).
    [Crossref]
  5. L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
    [Crossref]
  6. H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
    [Crossref]
  7. S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
    [Crossref]
  8. Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
    [Crossref]
  9. Y. J. Rao, “In-fibre Bragg grating sensors,” Meas. Sci. Technol. 8(4), 355–375 (1997).
    [Crossref]
  10. Y. J. Rao, “Recent progress in applications of in-fibre Bragg grating sensors,” Opt. Lasers Eng. 31(4), 297–324 (1999).
    [Crossref]
  11. B. Gu, M. Yin, A. P. Zhang, J. Qian, and S. He, “Optical fiber relative humidity sensor based on FBG incorporated thin-core fiber modal interferometer,” Opt. Express 19(5), 4140–4146 (2011).
    [Crossref] [PubMed]
  12. Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014).
    [Crossref] [PubMed]
  13. J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014).
    [Crossref] [PubMed]
  14. J. L. Kou, J. Feng, Q. J. Wang, F. Xu, and Y. Q. Lu, “Microfiber-probe-based ultrasmall interferometric sensor,” Opt. Lett. 35(13), 2308–2310 (2010).
    [Crossref] [PubMed]
  15. W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
    [Crossref]
  16. D. K. C. Wu, B. T. Kuhlmey, and B. J. Eggleton, “Ultrasensitive photonic crystal fiber refractive index sensor,” Opt. Lett. 34(3), 322–324 (2009).
    [Crossref] [PubMed]
  17. X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
    [Crossref]
  18. Y. Yu, X. Li, X. Hong, Y. Deng, K. Song, Y. Geng, H. Wei, and W. Tong, “Some features of the photonic crystal fiber temperature sensor with liquid ethanol filling,” Opt. Express 18(15), 15383–15388 (2010).
    [Crossref] [PubMed]
  19. B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
    [Crossref]
  20. G. L. Yin, S. Q. Lou, and H. Zou, “Refractive index sensor with asymmetrical fiber Mach–Zehnder interferometer based on concatenating single-mode abrupt taper and core-offset section,” Opt. Laser Technol. 45, 294–300 (2013).
    [Crossref]
  21. Y. J. Rao, “Recent progress in fiber-optic extrinsic Fabry-Perot interferometric sensors,” Opt. Fiber Technol. 12(3), 227–237 (2006).
    [Crossref]
  22. Y. J. Rao, M. Deng, D. W. Duan, X. C. Yang, T. Zhu, and G. H. Cheng, “Micro Fabry-Perot interferometers in silica fibers machined by femtosecond laser,” Opt. Express 15(21), 14123–14128 (2007).
    [Crossref] [PubMed]
  23. P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
    [Crossref]
  24. Z. L. Poole, P. Ohodnicki, R. Chen, Y. Lin, and K. P. Chen, “Engineering metal oxide nanostructures for the fiber optic sensor platform,” Opt. Express 22(3), 2665–2674 (2014).
    [Crossref] [PubMed]
  25. B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
    [Crossref] [PubMed]
  26. H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
    [Crossref]
  27. C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016).
    [Crossref]
  28. S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
    [Crossref]
  29. S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
    [Crossref]
  30. Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
    [Crossref]
  31. R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
    [Crossref]
  32. S. Piccarolo and G. Titomanlio, “Synergism in the swelling and solubility of poly (methyl methacrylate) in presence of ethanol/water mixtures,” Makromol. Chem., Rapid Cornmun. 3(6), 383–387 (1982).
    [Crossref]
  33. U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
    [Crossref]
  34. M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
    [Crossref]
  35. Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
    [Crossref]
  36. M. S. Ferreira, P. Roriz, J. Bierlich, J. Kobelke, K. Wondraczek, C. Aichele, K. Schuster, J. L. Santos, and O. Frazão, “Fabry-Perot cavity based on silica tube for strain sensing at high temperatures,” Opt. Express 23(12), 16063–16070 (2015).
    [Crossref] [PubMed]
  37. J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
    [Crossref]

2016 (4)

C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016).
[Crossref]

S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
[Crossref]

C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016).
[Crossref]

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

2015 (4)

S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
[Crossref]

M. S. Ferreira, P. Roriz, J. Bierlich, J. Kobelke, K. Wondraczek, C. Aichele, K. Schuster, J. L. Santos, and O. Frazão, “Fabry-Perot cavity based on silica tube for strain sensing at high temperatures,” Opt. Express 23(12), 16063–16070 (2015).
[Crossref] [PubMed]

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

2014 (6)

Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014).
[Crossref] [PubMed]

J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
[Crossref]

Z. L. Poole, P. Ohodnicki, R. Chen, Y. Lin, and K. P. Chen, “Engineering metal oxide nanostructures for the fiber optic sensor platform,” Opt. Express 22(3), 2665–2674 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

2013 (3)

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

G. L. Yin, S. Q. Lou, and H. Zou, “Refractive index sensor with asymmetrical fiber Mach–Zehnder interferometer based on concatenating single-mode abrupt taper and core-offset section,” Opt. Laser Technol. 45, 294–300 (2013).
[Crossref]

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

2012 (3)

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
[Crossref]

M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
[Crossref]

2011 (3)

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
[Crossref]

B. Gu, M. Yin, A. P. Zhang, J. Qian, and S. He, “Optical fiber relative humidity sensor based on FBG incorporated thin-core fiber modal interferometer,” Opt. Express 19(5), 4140–4146 (2011).
[Crossref] [PubMed]

2010 (5)

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

J. L. Kou, J. Feng, Q. J. Wang, F. Xu, and Y. Q. Lu, “Microfiber-probe-based ultrasmall interferometric sensor,” Opt. Lett. 35(13), 2308–2310 (2010).
[Crossref] [PubMed]

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Y. Yu, X. Li, X. Hong, Y. Deng, K. Song, Y. Geng, H. Wei, and W. Tong, “Some features of the photonic crystal fiber temperature sensor with liquid ethanol filling,” Opt. Express 18(15), 15383–15388 (2010).
[Crossref] [PubMed]

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
[Crossref]

2009 (1)

2007 (1)

2006 (1)

Y. J. Rao, “Recent progress in fiber-optic extrinsic Fabry-Perot interferometric sensors,” Opt. Fiber Technol. 12(3), 227–237 (2006).
[Crossref]

2004 (2)

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
[Crossref]

2002 (1)

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

1999 (1)

Y. J. Rao, “Recent progress in applications of in-fibre Bragg grating sensors,” Opt. Lasers Eng. 31(4), 297–324 (1999).
[Crossref]

1997 (1)

Y. J. Rao, “In-fibre Bragg grating sensors,” Meas. Sci. Technol. 8(4), 355–375 (1997).
[Crossref]

1982 (1)

S. Piccarolo and G. Titomanlio, “Synergism in the swelling and solubility of poly (methyl methacrylate) in presence of ethanol/water mixtures,” Makromol. Chem., Rapid Cornmun. 3(6), 383–387 (1982).
[Crossref]

Abraham, J. K.

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
[Crossref]

Ahn, H.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Aichele, C.

Alberto, N. J.

P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
[Crossref]

An, S.

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

André, P. S.

P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
[Crossref]

Antunes, P. F. C.

P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
[Crossref]

Asokan, S.

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

Ballauff, M.

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

Barnes, J. A.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Berger, T.

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

Bhat, N.

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

Bierlich, J.

Brown, R. S.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Chang, S. J.

C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016).
[Crossref]

Chen, K. P.

Chen, R.

Chen, W. G.

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

Chen, X. X.

Chen, Y. F.

Chen, Y. J.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Cheng, G. H.

Cheng, M. M.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Cheng, Y.

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

Chiang, K. S.

Chow, K. K.

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
[Crossref]

Deng, M.

Deng, Y.

Domingues, M. F. F.

P. F. C. Antunes, M. F. F. Domingues, N. J. Alberto, and P. S. André, “Optical fiber microcavity strain sensors produced by the catastrophic fuse effect,” IEEE Photonics Technol. Lett. 26(1), 78–81 (2014).
[Crossref]

Donatoc, N.

M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
[Crossref]

Duan, D. W.

Eggleton, B. J.

Fehrenbacher, U.

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

Feng, J.

Ferreira, M. S.

Frazão, O.

Fu, F.

Gao, Y.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Gelais, R. S.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Geng, Y.

Gong, Y.

C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016).
[Crossref]

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014).
[Crossref] [PubMed]

Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
[Crossref]

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
[Crossref]

Gu, B.

Guo, Y.

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
[Crossref]

He, S.

He, X. L.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Hong, X.

Hotte, A. L.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Hsueh, T. J.

C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016).
[Crossref]

Huang, W. P.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Jakob, T.

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

Jee, S. H.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Ji, W. B.

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
[Crossref]

Jin, C.

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

Jun, D. H.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Kang, Y. F.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Kheel, H.

S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
[Crossref]

Kim, D. J.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Kim, S. B.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Knoll, W.

U. Fehrenbacher, T. Jakob, T. Berger, W. Knoll, and M. Ballauff, “Refractive index and swelling of thin PMMA films in CO2/MMA mixtures at elevated pressures,” Fluid Phase Equilib. 200(1), 147–160 (2002).
[Crossref]

Ko, H.

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

Kobelke, J.

Kou, J. L.

Kuhlmey, B. T.

Latinoa, M.

M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
[Crossref]

Lee, C.

S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
[Crossref]

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

Lee, W. I.

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
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Leviatan, Y.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Li, C. M.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
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Li, J. P.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Li, Q. H.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Li, T. M.

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

Li, X.

Li, Z. Y.

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

Liang, X. H.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Lim, A.

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
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C. H. Lin, S. J. Chang, and T. J. Hsueh, “A low-temperature ZnO nanowire ethanol gas sensor prepared on plastic substrate,” Mater. Res. Express 3(9), 095002 (2016).
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Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
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Lin, Y.

Liu, F. M.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Liu, H. H.

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
[Crossref]

Liu, X. H.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Liu, X. L.

Liu, X. P.

Liu, Y.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
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R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
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Lou, J.

J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014).
[Crossref] [PubMed]

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G. L. Yin, S. Q. Lou, and H. Zou, “Refractive index sensor with asymmetrical fiber Mach–Zehnder interferometer based on concatenating single-mode abrupt taper and core-offset section,” Opt. Laser Technol. 45, 294–300 (2013).
[Crossref]

Lu, G. Y.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Lu, Y. Q.

Mackey, G.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
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Maru, Y.

S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
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S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
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S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
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M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
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M. Latinoa, R. Montaninia, N. Donatoc, and G. Neri, “Ethanol sensing properties of PMMA-coated fiber Bragg grating,” Prod. Eng. 47, 1263–1266 (2012).
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Ohodnicki, P.

Okazaki, S.

S. Masuzawa, S. Okazaki, Y. Maru, and T. Mizutani, “Catalyst-type-an optical fiber sensor for hydrogen leakage based on fiber Bragg gratings,” Sens. Actuators B Chem. 217, 151–157 (2015).
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Pan, S. S.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Park, J. H.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Park, S.

S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
[Crossref]

S. An, S. Park, H. Ko, C. Jin, W. I. Lee, and C. Lee, “Enhanced ethanol sensing properties of multiple networked Au-doped In2O3 nanotube sensors,” J. Phys. Chem. Solids 74(7), 979–984 (2013).
[Crossref]

Peng, G. D.

Peter, Y. A.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
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Philip, B.

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
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Piccarolo, S.

S. Piccarolo and G. Titomanlio, “Synergism in the swelling and solubility of poly (methyl methacrylate) in presence of ethanol/water mixtures,” Makromol. Chem., Rapid Cornmun. 3(6), 383–387 (1982).
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Poole, Z. L.

Poulin, A.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
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Qian, J.

Rao, Y. J.

C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016).
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B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
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B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014).
[Crossref] [PubMed]

Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
[Crossref]

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
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Y. J. Rao, M. Deng, D. W. Duan, X. C. Yang, T. Zhu, and G. H. Cheng, “Micro Fabry-Perot interferometers in silica fibers machined by femtosecond laser,” Opt. Express 15(21), 14123–14128 (2007).
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Y. J. Rao, “Recent progress in fiber-optic extrinsic Fabry-Perot interferometric sensors,” Opt. Fiber Technol. 12(3), 227–237 (2006).
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Y. J. Rao, “In-fibre Bragg grating sensors,” Meas. Sci. Technol. 8(4), 355–375 (1997).
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Reddy, C. C.

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
[Crossref]

Roriz, P.

Santos, J. L.

Saunders, J.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Schuster, K.

Shum, P.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Song, K.

Sood, A. K.

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

Sridevi, S.

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

Sun, G. J.

S. Park, G. J. Sun, H. Kheel, and C. Lee, “Fe2O3/Co3O4 composite nanoparticle ethanol sensor,” J. Korean Phys. Soc. 69(3), 373–380 (2016).
[Crossref]

Sun, P.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Titomanlio, G.

S. Piccarolo and G. Titomanlio, “Synergism in the swelling and solubility of poly (methyl methacrylate) in presence of ethanol/water mixtures,” Makromol. Chem., Rapid Cornmun. 3(6), 383–387 (1982).
[Crossref]

Tjin, S. C.

W. B. Ji, H. H. Liu, S. C. Tjin, K. K. Chow, and A. Lim, “Ultrahigh sensitivity refractive index sensor based on optical microfiber,” IEEE Photonics Technol. Lett. 24(20), 1872–1874 (2012).
[Crossref]

Tong, L.

J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014).
[Crossref] [PubMed]

Tong, W.

Varadan, V. K.

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
[Crossref]

Vasu, K. S.

S. Sridevi, K. S. Vasu, N. Bhat, S. Asokan, and A. K. Sood, “Ultra-sensitive NO2 gas detection using the reduced graphene oxide coated etched fiber Bragg gratings,” Sens. Actuators B Chem. 223, 481–486 (2016).
[Crossref]

Wan, Q.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Wang, L. W.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Wang, Q. J.

Wang, S. R.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Wang, T. H.

Q. Wan, Q. H. Li, Y. J. Chen, T. H. Wang, X. L. He, J. P. Li, and C. L. Lin, “Fabrication and ethanol sensing characteristics of ZnO nanowire gas sensors,” Appl. Phys. Lett. 84(18), 3654–3656 (2004).
[Crossref]

Wang, T. T.

Wang, Y.

J. Lou, Y. Wang, and L. Tong, “Microfiber optical sensors: a review,” Sensors (Basel) 14(4), 5823–5844 (2014).
[Crossref] [PubMed]

Wang, Z. G.

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

Wei, H.

Witchurch, A.

J. K. Abraham, B. Philip, A. Witchurch, V. K. Varadan, and C. C. Reddy, “A compact wireless gas sensor using a carbon nanotube/PMMA thin film chemiresistor,” Smart Mater. Struct. 13(5), 1045–1049 (2004).
[Crossref]

Wondraczek, K.

Wu, D. K. C.

Wu, H. J.

Wu, Y.

C. B. Yu, Y. Wu, X. L. Liu, B. C. Yao, F. Fu, Y. Gong, Y. J. Rao, and Y. F. Chen, “Graphene oxide deposited microfiber knot resonator for gas sensing,” Opt. Mater. Express 6(3), 727–733 (2016).
[Crossref]

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

Y. Gong, C. B. Yu, T. T. Wang, X. P. Liu, Y. Wu, Y. J. Rao, M. L. Zhang, H. J. Wu, X. X. Chen, and G. D. Peng, “Highly sensitive force sensor based on optical microfiber asymmetrical Fabry-Perot interferometer,” Opt. Express 22(3), 3578–3584 (2014).
[Crossref] [PubMed]

Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
[Crossref]

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
[Crossref]

Xu, F.

Yan, M.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Yang, J. H.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Yang, Q. Y.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Yang, S. S.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Yang, X. C.

Yao, B. C.

Yao, S. T.

Y. Liu, S. T. Yao, Q. Y. Yang, P. Sun, Y. Gao, X. H. Liang, F. M. Liu, and G. Y. Lu, “Highly sensitive and humidity-independent ethanol sensors based on In2O3 nanoflower/SnO2 nanoparticle composites,” RSC Advances 5(64), 52252–52258 (2015).
[Crossref]

Yin, G. L.

G. L. Yin, S. Q. Lou, and H. Zou, “Refractive index sensor with asymmetrical fiber Mach–Zehnder interferometer based on concatenating single-mode abrupt taper and core-offset section,” Opt. Laser Technol. 45, 294–300 (2013).
[Crossref]

Yin, M.

Yoon, H. J.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Yoon, Y. S.

H. Ahn, J. H. Park, S. B. Kim, S. H. Jee, Y. S. Yoon, and D. J. Kim, “Vertically aligned ZnO nanorod sensor on flexible substrate for ethanol gas monitoring,” Electrochem. Solid-State Lett. 13(11), J125–J128 (2010).
[Crossref]

Yu, C. B.

Yu, X.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Yu, Y.

Zeng, W.

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

Zhang, A. P.

Zhang, A. Q.

B. C. Yao, Y. Wu, Y. Cheng, A. Q. Zhang, Y. Gong, Y. J. Rao, Z. G. Wang, and Y. F. Chen, “All-optical Mach–Zehnder interferometric NH3 gas sensor based on graphene/microfiber hybrid waveguide,” Sens. Actuators B Chem. 194, 142–148 (2014).
[Crossref]

B. C. Yao, Y. Wu, A. Q. Zhang, Y. J. Rao, Z. G. Wang, Y. Cheng, Y. Gong, W. L. Zhang, Y. F. Chen, K. S. Chiang, and K. S. Chiang, “Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing,” Opt. Express 22(23), 28154–28162 (2014).
[Crossref] [PubMed]

Zhang, H.

W. Zeng, W. G. Chen, Z. Y. Li, H. Zhang, and T. M. Li, “Rapid and sensitive ethanol sensor based on hollow Au/V2O5 nanotubes via emulsion-electrospinning route,” Mater. Res. Bull. 65, 157–162 (2015).
[Crossref]

Zhang, M. L.

Zhang, S. M.

L. W. Wang, Y. F. Kang, X. H. Liu, S. M. Zhang, W. P. Huang, and S. R. Wang, “ZnO nanorod gas sensor for ethanol detection,” Sens. Actuators B Chem. 162(1), 237–243 (2012).
[Crossref]

Zhang, T. H.

Y. Wu, T. H. Zhang, Y. J. Rao, and Y. Gong, “Miniature interferometric humidity sensors based on silica/polymer microfiber knot resonators,” Sens. Actuators B Chem. 155(1), 258–263 (2011).
[Crossref]

Zhang, W. L.

Zhang, Y.

X. Yu, Y. Zhang, S. S. Pan, P. Shum, M. Yan, Y. Leviatan, and C. M. Li, “A selectively coated photonic crystal fiber based surface plasmon resonance sensor,” J. Opt. 12(1), 015005 (2010).
[Crossref]

Zhao, T.

Y. Gong, Y. Guo, Y. J. Rao, T. Zhao, and Y. Wu, “Fiber-optic Fabry–Pérot sensor based on periodic focusing effect of graded-index multimode fibers,” IEEE Photonics Technol. Lett. 22(23), 1708–1710 (2010).
[Crossref]

Zhou, J. J.

R. S. Gelais, G. Mackey, J. Saunders, J. J. Zhou, A. L. Hotte, A. Poulin, J. A. Barnes, H. P. Loock, R. S. Brown, and Y. A. Peter, “Gas sensing using polymer-functionalized deformable Fabry–Perot interferometers,” Sens. Actuators B Chem. 182, 45–52 (2013).
[Crossref]

Zhou, Z. X.

H. J. Yoon, D. H. Jun, J. H. Yang, Z. X. Zhou, S. S. Yang, and M. M. Cheng, “Carbon dioxide gas sensor using a graphene sheet,” Sens. Actuators B Chem. 157(1), 310–313 (2011).
[Crossref]

Zhu, T.

Zou, H.

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Figures (5)

Fig. 1
Fig. 1 (A) The schematic diagram of the FFPI sensor. (B) The reflective interference spectrum of the FFPI sensor.
Fig. 2
Fig. 2 The fabrication process of the FFPI sensor.
Fig. 3
Fig. 3 The experimental setup for gas sensing.
Fig. 4
Fig. 4 The experimental results of FFPI sensor for (A) ethanol, (B) acetone, (C) NH3, (D) CO and (E)H2 gas sensing.
Fig. 5
Fig. 5 (A) Dip shift and (B) ER change of the FFPI sensor as a function of the gas concentration increase. (C) The recoverability of the FFPI sensor.

Equations (2)

Equations on this page are rendered with MathJax. Learn more.

I ( λ ) = I F i b e r ( λ ) + I F i l m ( λ ) + 2 I F i b e r ( λ ) I F i l m ( λ ) cos ( 2 π O P D λ ) .
E R = 10 lg I max I min = 10 lg I F i b e r ( λ ) + I F i l m ( λ ) + 2 I F i b e r ( λ ) I F i l m ( λ ) I F i b e r ( λ ) + I F i l m ( λ ) 2 I F i b e r ( λ ) I F i l m ( λ ) .

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