Self-assembled nanomaterials for nonlinear fiber optics and tunable plasmonics

Islam Ashry; Chalongrat Daengngam; Ishac Kandas; James Heflin; Hans Robinson; Yong Xu

doi:10.1117/12.2024380

Translator Disclaimer

28 September 2013 Self-assembled nanomaterials for nonlinear fiber optics and tunable plasmonics

Islam Ashry, Chalongrat Daengngam, Ishac Kandas, James Heflin, Hans Robinson, Yong Xu

Author Affiliations +

Proceedings Volume 8845, Ultrafast Imaging and Spectroscopy; 88450D (2013) https://doi.org/10.1117/12.2024380
Event: SPIE Optical Engineering + Applications, 2013, San Diego, California, United States

Abstract

As an amorphous material with full inversion symmetry, silica-based microstructures cannot possess significant secondorder nonlinearity. We recently developed a method that can potentially overcome this deficiency by coating a silica fiber taper with layers of radially aligned nonlinear molecules. The coating process can be accomplished through layerby- layer self-assembly, where the alignment of the nonlinear molecules is maintained through electrostatic interaction. As a result, the nonlinear fiber structures are thermodynamically stable and can generate significant second-order nonlinear responses despite their full rotational symmetry. This prediction has been experimentally confirmed through SHG measurements. To further enhance the overall second-order nonlinearity, we have developed an UV-ablation-based approach that can generate second-order nonlinearity that is spatially periodic along the fiber taper. Our preliminary experiments suggest that SHG intensity can be enhanced by such quasi-phase-matching configurations.

We can also use the self-assembly approach to construct tunable plasmonic systems. As a proof-of-concept study, we assembled swellable polymer films over a planar Au substrate through layer-by-layer assembly and covered the swellable polymer with a monolayer of quantum dots. After immersing the swellable plasmonic structure in solution and adjusting its pH value, we used a fluorescence lifetime based approach to demonstrate that the thickness of the swellable polymers can be modified by almost 400%. The fluorescence lifetime measurements also confirmed that the plasmonic resonance can be significantly modified by the swellable polymers.

Citation Download Citation

Islam Ashry, Chalongrat Daengngam, Ishac Kandas, James Heflin, Hans Robinson, and Yong Xu "Self-assembled nanomaterials for nonlinear fiber optics and tunable plasmonics", Proc. SPIE 8845, Ultrafast Imaging and Spectroscopy, 88450D (28 September 2013); https://doi.org/10.1117/12.2024380

ACCESS THE FULL ARTICLE