Surface Plasmon Resonances in Oriented Silver Nanowire Coatings on Optical Fibers

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• 作者：Jean-Michel Renoirt ; Marc Debliquy ; Jacques Albert ; Anatoli Ianoul ; Christophe Caucheteur
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 22, 2014
• 年：2014
• 卷：118
• 期：20
• 页码：11035-11042
• 全文大小：433K
• 年卷期：v.118,no.20(May 22, 2014)
• ISSN：1932-7455

文摘

Silver nanowires 1鈥? 渭m in length and diameters of 0.04鈥?.05 渭m were synthesized by a polyol process and deposited on a single mode optical fiber with the Langmuir鈥揃lodgett technique. For nanowire surface coverage of 40% and partial orientation of their long axis obtained by controlling the deposition parameters, the optical properties of the nanowire coating become identical to those of a uniform metal coating obtained by sputtering or evaporation. Excitation of the nanowires by the polarized evanescent field of fiber cladding modes at near-infrared wavelengths near 1.5 渭m results in surface plasmon-like resonances in the transmission spectrum of the optical fiber. The polarization-dependent loss (PDL) spectrum of the tilted fiber Bragg grating used to excite the cladding modes shows a pronounced characteristic dip indicative of a plasmon resonance for radially polarized light waves and complete shielding of light for azimuthally polarized light. The PDL dip shifts at a rate of 650 nm/(refractive index unit) when the surrounding refractive index is changed, a 10-fold increase compared to uncoated fiber gratings and similar to that of uniform metal coated gratings. The advantage of the nanowire approach is to provide a much increased contact surface area for biomolecular recognition-based immunosensing.