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

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nanotechnology

Background:

• Previous studies explored monometallic thin films (Au, Ag) on tapered optical fibers.
• Bimetallic layers offer potential for enhanced optical properties.
• Liquid crystals provide tunable environments for optical devices.

Purpose of the Study:

• Investigate the influence of bimetallic (Au-Ag) layers on tapered optical fiber light propagation.
• Evaluate the impact of liquid crystal environment and applied voltage on spectral characteristics.
• Assess the novelty of bimetallic materials, their time stability, and technological parameter changes.

Main Methods:

• Fabrication of tapered optical fibers with 10 nm bimetallic (Au-Ag) layers.
• Integration into liquid crystal cells with voltage control (0-200 V) and modulation (5 Hz).
• Spectral measurements (550-1200 nm) at room temperature for various rubbed layer orientations (orthogonal, parallel, twist).

Main Results:

• Obtained spectral characteristics and resonant peaks for bimetallic layers.
• Compared results with monometallic films regarding resonant wavelength, peak width, SNR, and absorption.
• Analyzed the influence of liquid crystal orientation and applied voltage on optical response.

Conclusions:

• Bimetallic layers demonstrate unique light propagation characteristics in tapered optical fibers.
• Material stability and technological parameters significantly affect device performance.
• The study provides insights for developing advanced optical fiber sensors using bimetallic-liquid crystal configurations.