title: Long-period fiber grating sensor with a styrene-acrylonitrile nano-film incorporating cryptophane A for methane detection.
abstract: This paper presents a novel sensor design and application of long period fiber grating (LPFG) for detection of methane. A styrene-acrylonitrile nano-film incorporating cryptophane A, which is sensitive to methane in close vicinity to the surface, is constructed onto the cladding of long-period grating. For optimal design of the LPFG sensor, the relationship between the resonant wavelength shift and the complex refractive index of sensing film is analyzed based on the coupled-mode theory. The change in refractive index of the sensing film, induced by methane, can easily be obtained as a shift in resonance wavelength. The prepared LPFG sensor with time response of 50 s and good sensitivity (~0.375 nm %(-1)) suitable for the detection of methane below 3.5 vol. % is demonstrated. The response of the sensor (wavelength shift) is linear with methane concentration within our tested range and a detection limit of about 0.2% is estimated for the new sensor.
authors.affiliation: Key Laboratory for Optoelectronic Technology and Systems, Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China. jcyang@cqu.edu.cn
authors.forename: Jianchun
authors.initials: J
authors.lastname: Yang
authors.forename: Chuanyi
authors.initials: C
authors.lastname: Tao
authors.forename: Xueming
authors.initials: X
authors.lastname: Li
authors.forename: Guangqin
authors.initials: G
authors.lastname: Zhu
authors.forename: Weimin
authors.initials: W
authors.lastname: Chen
mesh_terms: D000181:Acrylonitrile / Q000737:chemistry*; D002138:Calibration; D005898:Glass / Q000737:chemistry*; D008697:Methane / Q000032:analysis*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D011083:Polycyclic Compounds / Q000737:chemistry*; D012031:Refractometry; D020058:Styrene / Q000737:chemistry*; D013997:Time Factors
chemical_list: D011083:Polycyclic Compounds; C545484:cryptophane A; C009753:fiberglass; D020058:Styrene; D000181:Acrylonitrile; D008697:Methane