Strong enhancement of nonlinear optical properties through supramolecular chirality
A new approach to second-order nonlinear optical (NLO) materials is reported, in which chirality and supramolecular organization play key roles. Langmuir-Blodgett films of a chiral helicene are composed of supramolecular arrays of the molecules. The chiral supramolecular organization makes the second-order NLO susceptibility about 30 times larger for the nonracemic material than for the racemic material with the same chemical structure. The susceptibility of the nonracemic films is a respectable 50 picometers per volt, even though the helicene structure lacks features commonly associated with high nonlinearity. Susceptibility components that are allowed only by chirality dominate the second-order NLO response.
Verbiest
T
T. Verbiest, S. Van Elshocht, M. Kauranen, L. Hellemans, J. Snauwaert, A. Persoons, Laboratory of Chemical and Biological Dynamics, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Heverlee, Belgium. C. Nuckolls and T. J.
Elshocht
SV
Kauranen
M
Hellemans
L
Snauwaert
J
Nuckolls
C
Katz
TJ
Persoons
A