A low-cost, high-sensitivity humidity sensor based on a low-loss dielectric thin film waveguide (WG) is presented. The guided mode is produced by coupling laser light into the film by optical tunneling through a solid gap deposited on the base of a semi-cylindrical lens. The light reflected from this optical system carries information about the refractive index of the medium neighboring the WG,...

The humidity sensor made of polymer optical fiber Bragg grating (POFBG) responds to the water content change in fiber induced by the change of environmental condition. The response time strongly depends on fiber size as the water change is a diffusion process. The ultrashort laser pulses have been providing an effective microfabrication method to achieve spatial localized modification in materi...

The effect of pore size and uniformity on the response of nanoporous alumina, formed on aluminum thick films through an anodization process, to ammonia and humidity at room temperature is reported. Pore sizes examined range from 13 nm to 48 nm, with pore size standard deviations ranging from 2.6 nm to 7.8 nm. The response of the material to ammonia and humidity is a strong function of pore size...

Measuring humidity in dynamic situations calls for highly sensitive fast response sensors. Here we report, a humidity sensor fabricated using solution processed supramolecular nanofibres as active resistive sensing material. The nanofibres are built via self- assembly of donor and acceptor molecules (coronene tetracarboxylate and dodecyl methyl viologen respectively) involved in charge transfer...

The motivating principle behind this research is the development of a small, wearable sensor that would use humidity and temperature measurements as metrics for health monitoring. We have successfully fabricated macro-scale devices via pressing of a polymer between two aluminum plates, and the responses of these capacitors were tested in various humidity conditions. The transition from macro to...

Metal-doped zinc oxide (ZnO) nanorod arrays have attracted much attention due to improvement in their electrical, structural, and optical properties upon doping. In this chapter, we discuss the effects of aluminum (Al)and iron (Fe)-doping on ZnO nanorod arrays properties particularly for humidity sensor applications. Compared to Fe, Al shows more promising characteristics as doping element for ...