An optically integrated NH3 sensor using WO3 thin films as sensitive material

• Published in: Journal of optics. A, Pure and applied optics Vol. 10; no. 10; pp. 104016 - 104016 (6)
• Main Authors: Lazcano-Hernández, H E, Sánchez-Pérez, C, García-Valenzuela, A
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Bristol IOP Publishing 01.10.2008; Institute of Physics
• Subjects: Applied sciences; Circuit properties; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Integrated optics. Optical fibers and wave guides; Optical and optoelectronic circuits; Optical elements, devices, and systems; Optical waveguides and coupleurs; Optics; Physics; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Integrated optics; Refractive index; optic integrated; Glass; Transmittance; Optical waveguides; Thin films; Ammonia; optic waveguide; gas sensors; Cavity resonators; Optical sensors; Optical constants; Gas detector
• ISSN: 1464-4258; 1741-3567
• DOI: 10.1088/1464-4258/10/10/104016

We analyze the optical response of WO3 sputtered thin films to NH3 gas sensing through transmittance changes. By sputtering, films with a combination of monoclinic and triclinic crystalline structure were obtained. The films show sensitivity to NH3 presence at the wavelengths lambda = 980 nm and 1550 nm and at low temperature, T = 90 deg C. The optical constants (refractive index (n) and absorbant coefficient (alpha)) were calculated using the transmittance spectra and the model of a simple resonator. According to these results, an integrated optical NH3 sensor based on a glass waveguide with a WO3 thin film deposited at the surface was designed and experimentally characterized.