Relative humidity sensor based on surface plasmon resonance of D-shaped fiber with polyvinyl alcohol embedding Au grating

Ultrasensitive Dual‐Mode Humidity Detection Using a Plasmonic‐Photonic Hybrid Waveguide

“…Here, PPHS-based dualmode RH detection offers a unique tool for isolating the individual contribution of RI variation and volume expansion in the www.advopticalmat.de process of moisture absorption, which cannot be distinguished by conventional single-mode detections. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Figure 4a,b indicates a pure thickness-induced effect and pure RI-induced effect on 4th-order WG and SPP modes by FDTD simulations. Clearly, for a PPHS with a thick PVA film (h > 850 nm), SPP mode is independent of the thickness of PVA film (Figure 4a, top) and thus completely determined by the RI of PVA (Figure 4b, top).…”

“…For optical sensing, two effects, permittivity variation and volume expansion, can be easily detected by tracking the resonant wavelength or light intensity in the process of absorption moisture. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] For example, integrated with moisture-sensitive coating, several photonic architectures such as plasmonic structure, [8][9][10][11][12][13][14][15] photonic crystal cavity, [16][17][18][19][20] Fabry-Pérot (FP) cavity, [21] fiber Bragg's grating, [22][23][24] and long periodicity grating [25,26] have been explored as humidity sensors. For this type of humidity sensor, refractive index (RI) variation and volume expansion are considered to be concurrent and play counteracting roles in tailoring the resonant wavelength of optical modes.…”

A Poly(vinyl alcohol) Coating Method for a Tilted‐Fiber Bragg‐Grating‐Assisted Fiber Hygrometer

“…[ 1,2 ] One of the common fiber hygrometer operating principles is the monitoring of changes in the refractive index of a hygroscopic coating deposited onto the surface of a fiber sensor. [ 3–15 ] Various substances can be used as a functional coating material, such as poly(vinyl alcohol) (PVA), [ 4–13 ] agarose, [ 14 ] graphene oxide, [ 15,16 ] titanium dioxide (TiO 2 ), [ 16,17 ] polyimide, [ 18–21 ] and others. [ 22,23 ] In this article, we used PVA, the refractive index of which varies from 1.453 to 1.358, whereas RH changes from 20% to 90%.…”

Relative Humidity Measurement Based on a Tapered, PVA-Coated Fiber Optics Multimode Interference Sensor

“…Sensing RH with optical waveguides has been achieved by incorporating special materials that respond to changes in RH into various types of optical fiber-based sensing schemes. For example, polyvinyl alcohol (PVA) is a bio-compatible substance, soluble in water, that has been used successfully for RH fiber optic sensors [9,10].…”