Miniature high-sensitivity optical fiber chemical sensor

Abstract

The invention relates to a miniature high-sensitivity optical fiber chemical sensor, belonging to the technical field of the miniature sensor. The chemical sensor particularly contains a fiber taper, an optical fiber resonant cavity, a top cover and a base, wherein the optical fiber resonant cavity is a single mode fiber without a coating layer and the middle part of the single mode fiber is plated with a zeolite membrane, thus the selective adsorption ability of the chemical sensor can be effectively increased. The chemical sensor adopts the fiber taper as stimulating waveguide to stimulate the whispering gallery chamber of the resonant cavity and has high coupling efficiency. The selective absorption effect of the zeolite coating is utilized to detect gas molecules with certain sizes. The base and top cover which are used as the loading device have simple structure and are prepared by the standard mechanical processing technology. The sensor in the invention can realize high sensitivity and high precision detection; the sensor can be used to detect the existence and concentration of a certain type of molecules in the environment; and the sensor can be widely applied in the fields such as environmental control, industrial process treatment, mine production, public safety devices and homeland security, and the sensitivity of the sensor can reach the ppm-order or even the ppb-order.

Description

technical field [0001] The invention relates to a miniature high-sensitivity optical fiber chemical sensor, which belongs to the technical field of miniature sensors. Background technique [0002] Commonly used optical resonator structures include disks, rings, columns, spheres, etc. These gyratory resonators support high quality factor whispering gallery modes (WGMs for short). WGMs are an optical resonant mode that depends on topographical resonance, and the resonant frequency (or wavelength) of this mode depends on the size of the resonant cavity and the refractive index distribution inside and outside the cavity. The waveguide structures commonly used to excite the resonator WGM through the evanescent field include fiber cones, prisms, side-polished fibers, etc. (Ilchenko V S, et al. Optical Resonators With Whispering-Gallery Modes--Part II: Applications.IEEE, Journal of Selected Topics in Quantum Electronics, 12(1):15-32, 2006). It was also proposed to use long-period...

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Problems solved by technology

[0003] Chemical sensors based on resonant cavities such as spheres / disks / rings / columns can achieve extremely low concentration detection (Hanumegowda N M, et al. Refractometric sensors based on microsphere resonators, Applied Physics Letters, 87(201107): 1-3, 2005 ), but cannot achieve selective detection of molecules of a specific size

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