Optofluidic refractive index sensor with microtube-coupled suspended core fiber

Abstract

Based on optofluidics and whispering gallery mode (WGM) theory, here an optofluidic refractive index sensor with microtube-coupled suspended core fiber (SCF) is proposed. It solves the issues of general sensors with microcavity-coupled fiber taper such as too fragile, unstable performance due to open coupling, poor portability and repeatability, while overcoming the poor performance of low refractive index sensing in general full-package fiber sensors. The sensor only needs a very small amount of liquid sample (about 1.8 nL). The proposed sensor combines the excellent performance of full package, optofluidics and WGM resonator. The resonant characteristics and sensing performance of the sensor are analyzed and discussed by the theoretical simulation. The simulation results indicate that the sensor has a wide refractive index sensing range (1.330–1.700) and good performance. The resonance wavelength shift has a good linear relationship with the liquid refractive index variation. In the low refractive index region, the sensitivity is 222.5–247.5 nm/RIU, Q-factor is 1.03×10³ and the detection limit is 3.64×10⁻⁴ RIU. In the medium and high refractive index regions, the sensitivity is 564.4–846.2 nm/RIU, Q-factor is up to 8.62×10⁴, and the detection limit can be as low as 1.29×10⁻⁶ RIU. The sensor exhibits a high sensitivity, a high Q-factor and a very low detection limit.

Keywords

optofluidics and whispering gallery mode / optofluidic refractive index sensor

References

[1] YangY, WangZ J, ZhangX B, et al.. Recent progress of in-fiber WGM microsphere resonator. Frontiers of optoelectronics, 2023, 16110. J]

[2] LiuY, YangH H, LuY L, et al.. A whispering gallery mode strain sensor based on microtube resonator. Optoelectronics letters, 2021, 17(04): 199-204. J]

[3] DangH T, WangY X, ChenF J, et al.. Humidity sensing characteristics of compact coupled optical fiber structure by microsphere and tapered capillary tube. Measurement, 2024, 2328. J]

[4] YinQ Y, CaiL, LiS W, et al.. An in-fiber whispering-gallery-mode microsphere resonator and its sensing characteristics. Acta optica sinica, 2023, 43(1): 31-40[J]

[5] MerabetN A, CherbiL, BenlachehebM. High sensitivity optical fiber microring sensor based on whispering-gallery mode for water analysis. Optical Sensors Conference 2021, April 19–23, 2021, Online, 2021, Washington. SPIE. 11772[C]

[6] ChakrabartiK, ObaidatM, MostufaS, et al.. Design and analysis of a multi-core whispering gallery mode bio-sensor for detecting cancer cells and diabetes tear cells. OSA continuum, 2021, 4(8): 2294-2307. J]

[7] LiaoJ X, FengL, YangJ N. High power fiber-coupled diode laser based on beam shaping simulation. Optical engineering, 2023, 6269. J]

[8] ZhangY N, ZhuN S, ZhouT M, et al.. Research on fabrication and sensing properties of fiber-coupled whispering gallery mode microsphere resonator. IEEE sensors journal, 2020, 20(2): 833-841. J]

[9] BaiM X, JinL Y, LiJ L, et al.. Highly sensitive temperature sensor based on polymer spherical microcavity. Infrared and laser engineering, 2022, 51(10): 69-75[J]

[10] TangJ K, QiuG Y, WangJ. Recent development of Optofluidics for imaging and sensing applications. Chemosensors, 2022, 10115. J]

[11] WanH D, ChenJ J, WanC, et al.. Optofluidic microcapillary biosensor for labelfree, low glucose concentration detection. Biomedical optics express, 2019, 10(8): 3929-3937. J]

[12] MuhammadA R, RusdiM F, JafryA A A, et al.. Evanescent field interaction of 1550 nm pulsed laser with silver nanomaterial coated D-shape fiber. Infrared physics and technology, 2021, 119103920. J]

[13] GaoD, LeiH, ZhangJ, et al.. Side polished graded index multimode fiber based refractive index sensor for biology measurement. Journal of optical technology, 2018, 85(12): 780-788. J]

[14] LiH WResearch on Optofluidic biosensor based on microcapillary, 2010, Tianjin. Tianjin University. [D]

[15] ZhuX SResearch on the sensing applications of higher-order whispering gallery mode, 2020, Nanjing. Nanjing University. [D]

RIGHTS & PERMISSIONS

Tianjin University of Technology