@inproceedings{dd919b1282ff4554864add39bb5925a8,
title = "Exploration of higher-order mode coupling in long-period gratings for sensitive monitoring of polyelectrolyte self-assembly at nanoscale",
abstract = "Layer-by-layer (LbL) self-assembly via hydrogen bonding is one of the primary mechanisms to achieve stimuliresponsive polyelectrolyte thin films for a variety of applications. The ability to monitor the individual LbL steps in situ is of great significance in the development and understanding of hydrogen-bonded LbL systems of new design functions and properties. Long-period gratings in single-mode fiber (SMF-LPG) has the potential for such application by virtue of its high index sensitivity. We report a theoretical and experimental investigation to sort out the coupled cladding mode that is most sensitive to molecular adsorption events during LbL deposition. We have undertaken a combined theoretical and experimental investigation to illustrate and demonstrate the strong correlation between the order of the coupled cladding modes in long-period gratings (LPG) in conventional single mode fiber and their sensitivity to the process of layer-by-layer (LbL) assembly of polyelectrolyte multi-layers. We show that high-order cladding modes such as LP0,10 in LPG are significantly more sensitive than their lower-order counterparts such as LP0,2, with LP0,10 yielding a shift of 1.575 nm in resonance wavelength per polyelectrolyte repeating unit of poly(vinyl pyrrolidone)/poly(methacrylic acid) bi-layer. We illustrate the potential utility of SMF-LPG integrated with stimuli-responsive LbL thin films as sensors. The integrated LPG/LbL strategy as a robust LbL test-bed has broad ramifications in exploring and exploiting sensors and devices enabled by versatile, stimuli-responsive polyelectrolyte thin films.",
keywords = "Long-period grating, layer-by-layer self-assembly, mode coupling, polyelectrolyte, single mode fiber",
author = "Fei Tian and Jiri Kanka and Xiangzhi Li and Henry Du",
year = "2014",
doi = "10.1117/12.2053471",
language = "English",
isbn = "9781628410358",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
booktitle = "Fiber Optic Sensors and Applications XI",
note = "Fiber Optic Sensors and Applications XI ; Conference date: 08-05-2014 Through 09-05-2014",
}