Refractometric Optical Sensing by using a Multilayer Reflection and Transmission Narrowband Filter

Abstract

A refractometric optical sensing device based on a multilayer narrowband reflection and transmission filter with an ultrathin metallic film is proposed. By changing the refractive index of the defect layer in this narrowband filter, we find that the shift in the resonance peak wavelength is a sensitive function of the small variation in the refractive index. This sensing method is more compact and easier to make than the usual one based on the photonic crystal sensor.