SPR Sensor Based on a Tapered Optical Fiber with a Low Refractive Index Liquid Crystal Cladding and Bimetallic Ag–Au Layers

Abstract

This paper presents a study of the influence of bimetallic layer covers of a tapered optical fiber surrounded by a low refractive index liquid crystal on the properties of light propagation in the taper structure. This research follows previous works on the effect of monometallic thin films (Au and Ag). In this case, the total thicknesses of the bimetallic layers were h = 10 nm, and the participation of gold and silver was equal. The films were deposited on one side of the tapered waist area. The liquid crystal cells were controlled with a voltage U from 0 to 200 V, with and without amplitude modulation at a frequency of fmod = 5 Hz. For the purposes of this research, spectral characteristics were obtained for a wavelength λ ranging from 550 to 1200 nm. Measurements were carried out at room temperature for three types of rubbed layers orientation—orthogonal, parallel, and twist in relation to the fiber axis. Obtained resonant peaks were compared with the previous results regarding the resonant wavelength, peak width, SNR, and maximum absorption. In the presented paper, the novelty is mainly focused on the materials used and their time stability, as well as corresponding changes in the technological parameters used.

Structure Design and Sensitivity Optimization of Optical Fiber Biosensor Based Au Nano Column - TiO2 Heterostructure

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Study and simulation of the effects of geometry and materials on the detection potential of tapered fiber sensors

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Towards Femtoscan-Assisted Analysis of Liquid Crystal Self-Organization on Different Polymer and Glass Surfaces for Lab-on-a-Chip and Lab-on-a-Dish Applications, Including Optofluidic and Flexoelectric Ones

“…Protein determination systems based on molecularly imprinted polymer recognition combined with birefringence liquid crystal detection [74] and liquid crystal microdroplets coated with block liquid crystalline polymers by protein adsorption for sensor applications [75]. Some LC-assisted protein detection techniques (including on-chip detection) can also be implemented using surface plasmon resonance principles [76]. 6.…”