1 October 1997 Fiber optic pH sensors using thin-film Langmuir-Blodgett overlay waveguides on single-mode optical fibers
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Abstract
A fiber-optic pH sensor is demonstrated using thin film Langmuir-Blodgett (LB) films to form a single-mode planar waveguide, evanescently coupled to a side-polished single- mode optical fiber. The LB technique shows two distinct advantages in the fabrication of such sensors, the ability to control the overlay waveguide thickness to a single molecular layer (approximately 3 nm) and also, as the materials used are organic, the ability to engineer specific materials for different sensing purposes. The response of the sensor is also investigated through changes in the overlay refractive index, caused by changes in its absorption spectrum via a simple Kramers-Kronig model. The model is shown to be able to predict the response of the sensor.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Damian Flannery, Stephen W. James, Ralph P. Tatam, Geoffrey J. Ashwell, "Fiber optic pH sensors using thin-film Langmuir-Blodgett overlay waveguides on single-mode optical fibers", Proc. SPIE 3133, Optical Thin Films V: New Developments, (1 October 1997); doi: 10.1117/12.279109; https://doi.org/10.1117/12.279109
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