Refraction index sensor based on phase resonances in a subwavelength structure with double period

DIANA SKIGIN; MARCELO LESTER

APPLIED OPTICS

OPTICAL SOC AMER

Lugar: Washington; Año: 2016 vol. 55 p. 8133 - 8137

0003-6935

In this paper, we numerically demonstrate a refraction index sensor based on phase resonance excitation in asubwavelength-slit structure with a double period. The sensor consists of a metal layer with subwavelength slotsarranged in a bi-periodic form, separated from a high refraction index medium. Between the metallic structure andthe incident medium, a dielectric waveguide is formed whose refraction index is going to be determined. Variationsin the refraction index of the waveguide are detected as shifts in the peaks of transmitted intensity originated byresonant modes supported by the compound metallic structure. At normal incidence, the spectral position of theseresonant peaks exhibits a linear or a quadratic dependence with the refraction index, which permits us to obtain theunknown refraction index value with a high precision for a wide range of wavelengths. Since the operatingprinciple of the sensor is due to the morphological resonances of the slits? structure, this device can be scaledto operate in different wavelength ranges while keeping similar characteristics.