Supramolecular Micro-/Nano- Fibers for Nonlinear Optics
Jialiang Xu*, Theo Rasing, Alan E. Rowan.
Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen, The
Netherlands
Email: J.Xu@Science.ru.nl
Since the advent of the laser and the subsequent discovery of nonlinear optics (NLO), there has been an
untiring search for novel NLO materials. Subwavelength micro-/nano- fiber-like structures are of
critical importance as building blocks for light generation, propagation, amplification, and modulation.
Currently most photonic components are based on inorganic nonlinear optical materials, though
organic materials intrinsically have higher hyperpolarizabilities, come with diverse architectures, and
show very fast NLO responses. The challenge for organic NLO materials lies in the use of weak
noncovalent interactions between the organic molecules to construct suitable and stable organizations
for generating NLO effects, in particular second-order ones for which non-centrosymmetric
arrangements are essential. We intend to pursue supramolecular approaches, which are summarized by
the combination of complementary nonconvalent interactions with a “1+1>2” amplification, to
constructing organic based multi-responsive NLO micro-/nano- fiber materials.
Two types of supramolecular systems are proposed for construction of multifunctional nonlinear
optics, namely self-assemblies and helical polyisocyanopeptide scaffolds. Multi-chromophores are
arranged into suitable organizations in both systems, with the assistance of subtle supramolecular
interactions, for generation of both second- and third- order NLO. More importantly, the
supramolecular systems are fabricated into subwavelength scale 1-D superstructures by facile solution
processed self-assembly or electro-spinning techniques. The resulted microfibers will be ideal
platforms for combined NLO, waveguiding, and lasing cavity. Detailed polarization dependence
analysis also demonstrates that the well-oriented dipole moments in both ground and excited states are
vital for the generation and tunability of the combined NLO.
Several internship projects at master stage students are available. You are going to work
multidisciplinary at the interface of synthetic chemistry (molecular and supramolecular synthesis),
materials science, and nanophotonics. If you are interested, please contact: Dr. Jialiang Xu
(J.Xu@Science.ru.nl) or Prof. Alan E. Rowan
(a.rowan@science.ru.nl)
Figure 1. a) Fluorescent microscope images of nanoarchitectures with brilliant optical properties;
b) Nonlinear optical upconversion responses.
References:
[1] J. Xu, S. Semin, D. Niedzialek, P. H. J. Kouwer, E. Fron, E. Coutino, M. Savoini, Y. Li, J. Hofkens,
H. Uji-I, D. Beljonne, T. Rasing, A. E. Rowan. Adv. Mater., 25, (2013), p. 2084.
[2] E. Schwartz, M. Koepf, H. J. Kitto, R. J. M. Nolte, A. E. Rowan. Polym. Chem., 2, (2011), p. 33