A new generation of surface plasmonic optical fibre sensors is fabricated using multiple coatings deposited on a lapped section of a single mode fibre. Post-deposition UV laser irradiation using a phase mask produces a nano-scaled surface relief grating structure, resembling nano-wires. The overall length of the individual corrugations is approximately 14 μm with an average full width half maximum of 100 nm. Evidence is presented to show that these surface structures result from material compaction created by the silicon dioxide and germanium layers in the multi-layered coating and the surface topology is capable of supporting localised surface plasmons. The coating compaction induces a strain gradient into the D-shaped optical fibre that generates an asymmetric periodic refractive index profile which enhances the coupling of the light from the core of the fibre to plasmons on the surface of the coating. Experimental data are presented that show changes in spectral characteristics after UV processing and that the performance of the sensors increases from that of their pre-UV irradiation state. The enhanced performance is illustrated with regards to change in external refractive index and demonstrates high spectral sensitivities in gaseous and aqueous index regimes ranging up to 4000 nm/RIU for wavelength and 800 dB/RIU for intensity. The devices generate surface plasmons over a very large wavelength range, (visible to 2 μm) depending on the polarization state of the illuminating light.
|Title of host publication||Nanoengineering|
|Subtitle of host publication||fabrication, properties, optics, and devices X|
|Editors||Eva M. Campo, Elizabeth A. Dobisz, Louay A. Eldada|
|Place of Publication||Bellingham, WA (US)|
|Number of pages||8|
|Publication status||Published - 2013|
|Event||Nanoengineering: fabrication, properties, optics, and devices X - San Diego, CA, United States|
Duration: 27 Aug 2013 → 29 Aug 2013
|Name||Proceedings of SPIE|
|Conference||Nanoengineering: fabrication, properties, optics, and devices X|
|City||San Diego, CA|
|Period||27/08/13 → 29/08/13|
Bibliographical noteT. Allsop ; R. Neal ; C. Mou ; M. Dvorak ; A. Rozhin ; K. Kalli and D. J. Webb
"Generation and performance of localised surface plasmons utilising nano-scale structured multi-layered thin films deposited upon D-shaped optical fiber", Proc. SPIE 8816, Nanoengineering: Fabrication, Properties, Optics, and Devices X, 881613 (September 26, 2013).
Copyright 2013 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Funding: EPSRC Joint Research Grant: EP/J010413/1 9Title: Grating and waveguide plasmonic sensors). European Regional Development Fund (CEITECCZ.1.05/1.1.00/02.0068) and the EU 7th Framework Programme (SYLICA and 280566 - UnivSEM).