An ethanol vapor detection probe based on a ZnO nanorod coated optical fiber long period grating

Abstract

A new ethanol vapor detection probe based on an optical fiber long period grating overlaid with a zinc oxide (ZnO) nanorods layer is presented. The ZnO nanorod layer was developed onto the cladding of the fiber using aqueous chemical growth, seeded by a thin layer of metallic Zn. The growth of the ZnO nanorods overlayer onto the long period grating cladding is monitored in real time for investigating its effect on the spectral properties of the device and its subsequent role in the sensing mechanism. Results are presented, on the correlation between the growth time of the ZnO layer and the ethanol vapor detection performance. Reversible spectral changes of the notch extinction ratio of more than 4 dB were recorded for ~50 Torr of ethanol vapor concentration. In addition, photoluminescence emission studies of the ZnO overlayer performed simultaneously with the optical fiber spectral measurements, revealed significant ethanol induced changes in the intensity of the bandgap peak.

Biosensing with optical fiber gratings

“…An LPG-based fiber probe sensor coated with a zinc oxide (ZnO) nanorod (~100 nm in height) layer was used to detect ethanol vapor [41]. When the sensor is exposed to ethanol vapor, the optical properties of the LPG, i.e.…”

Highly sensitive volatile organic compounds vapour measurements using a long period grating optical fibre sensor coated with metal organic framework ZIF-8

“…There have been a number of fibre-optic based ethanol gas sensors proposed recently using the deposition of the sensitive layer on the fibre tip to form Fabry-Perot interferometers [14][15][16][17][18] or evanescent wave sensors, where part of the cladding is mechanically or chemically removed and then the functional coating is deposited over the stripped region [11,[19][20][21][22]. A coating sensitive to ethanol vapours has been also applied on the surface of a photonic crystal fibre [23], long period grating (LPG) [24] or quartz crystal microbalance (QCM). The properties of pub- n/a n/a [11] Cladding removed PMMA optical fibre in intensity at selected wavelengths Sm2O3 0 to 500 ppm 76 × 10 −3 au/ppm 78 min n/a [20] Cladding removed PMMA optical fibre in intensity at selected wavelengths Graphene oxide 100 to 500 ppm 0.26 a.u./ppm n/a n/a [21] Cladding removed silica optical fibre in power at selected wavelength Max shift of 59 nm/pure EtOH gas n/a n/a [23] lished ethanol gas fibre optic based sensors (and one example of a QCM) are summarized in Table 1.…”

“…The properties of pub- n/a n/a [11] Cladding removed PMMA optical fibre in intensity at selected wavelengths Sm2O3 0 to 500 ppm 76 × 10 −3 au/ppm 78 min n/a [20] Cladding removed PMMA optical fibre in intensity at selected wavelengths Graphene oxide 100 to 500 ppm 0.26 a.u./ppm n/a n/a [21] Cladding removed silica optical fibre in power at selected wavelength Max shift of 59 nm/pure EtOH gas n/a n/a [23] lished ethanol gas fibre optic based sensors (and one example of a QCM) are summarized in Table 1. Reported sensors suffer mostly from a high response time in a range of 10 s min [19,24] and are usually tested over a limited concentration range. For example, they are tested at saturated vapour conditions [18,24], high (in a range of thousands of ppm) [22,23,26] or low level concentrations usually below 500 ppm [11,14,[19][20][21].…”

“…Reported sensors suffer mostly from a high response time in a range of 10 s min [19,24] and are usually tested over a limited concentration range. For example, they are tested at saturated vapour conditions [18,24], high (in a range of thousands of ppm) [22,23,26] or low level concentrations usually below 500 ppm [11,14,[19][20][21]. The comparison in sensitivity shown in Table 1 is limited as only two papers show the limit of detection of 2.74 [16] and 380 ppm [17].…”

Fabry-Perot Vapor Microsensors Fabricated onto Fibre Endface by Multiphoton Polymerization Technique

“…We explore these endface fibre sensing probes for tracing common organic solvents [3]. The devices developed have been optimised for operation at the spectral region lying between 1415nm to1655nm, while being interrogated in reflection mode using a simple 50/50 fibre coupler.…”