Mihaela A. Ghelmez Kungliga Tekniska Hoegskolan (Romania) Maria Honciuc Polytechnic Institute of Bucharest (Romania) Mihai C. Piscureanu Politehnica Univ. of Bucharest (Romania) Cristian Gheorghe Clinical Hospital Fundeni Bucharest (Romania)
There is current interest in organic materials for use in optoelectronics.
The dielectric properties of these materials have proved
compatible with low biasing powers, and some methods to improve them
have been proposed. We discuss some fatty acids and mixtures of fatty
acids, as well as fatty acid–cholesterol, all of them having an important
role in biological membranes. They have smectic liquid-crystalline properties
in some temperature ranges, this state being involved in the
mechanisms determining health and illness. They can be used also in
optoelectronic applications, because of the huge optical nonlinearity in
the mesomorphic domain. The external self-focusing of a laser beam
and nonlinear optical activity have been observed experimentally; by
studying the modification of laser pulses in such media, the cholesterol
percentage could be estimated. Also the interaction, at different wavelengths,
with coherent and noncoherent light was studied.