2018 Impact factor 1.686
Soft Matter and Biological Physics

Eur. Phys. J. E 3, 245-251

Nonlinear optical properties of a channel waveguide produced with crosslinkable ferroelectric liquid crystals

V.S.U. Fazio1,2 - S.T. Lagerwall1 - V. Zauls3 - S. Schrader3 - P. Busson4 - A. Hult4 - H. Motschmann2

1 Department of Microelectronics and Nanoscience, Liquid Crystal Physics, Chalmers University of Technology & Göteborg University, SE-41296 Göteborg, Sweden
2 Max-Plank-Institute of Colloids and Interfaces, D-14476 Golm/Potsdam, Germany
3 Institute of Physics, University of Potsdam, D-14469 Potsdam, Germany
4 Department of Polymer Technology, Royal Institute of Technology, SE-10044, Stockholm, Sweden
hubert.motschmann@mpikg-golm.mpg.de

Received 7 March 2000

Abstract
A binary mixture of ferroelectric liquid crystals (FLCs) was used for the design of a channel waveguide. The FLCs possess two important functionalities: a chromophore with a high hyperpolarizability $\beta$ and photoreactive groups. The smectic liquid crystal is aligned in layers parallel to the glass plates in a sandwich geometry. This alignment offers several advantages, such as that moderate electric fields are sufficient to achieve a high degree of polar order. The arrangement was then permanently fixed by photopolymerization which yielded a polar network possessing a high thermal and mechanical stability which did not show any sign of degradation within the monitored period of several months. The linear and nonlinear optical properties have been measured and all four independent components of the nonlinear susceptibility tensor $\overline d$ have been determined. The off-resonant d-coefficients are remarkably high and comparable to those of the best known inorganic materials. The alignment led to an inherent channel waveguide for p-polarized light without additional preparation steps. The photopolymerization did not induce scattering sites in the waveguide and the normalized losses were less than 2dB/cm. The material offers a great potential for the design of nonlinear optical devices such as frequency doublers of low-power laser diodes.

PACS
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order - 42.65.Ky Harmonic generation, frequency conversion - 42.82.Et Waveguides, couplers and arrays

Copyright EDP Sciences, Società Italiana di Fisica, Springer-Verlag