Table of Contents
Laser Chemistry
Volume 17, Issue 1, Pages 1-18
http://dx.doi.org/10.1155/1997/37594

Dispersion of Third Order Optical Nonlinearity of Pseudoisocyanine J-Aggregates

1Vilnius University, Laser Research Center, Sauletekio ave. 10, Vilnius LT-2054, Lithuania
2Fachhochschule Jena, Fachbereich Medizintechnik/Physikalische Technik, Tatzendpromenade 1b, Jena D-07745, Germany

Received 17 April 1996

Copyright © 1997 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Dispersion of degenerate four-wave mixing (DFWM) efficiency near the exciton resonance of aggregates of 1,1-diethy1-2-2-cyanine (pseudoisocyanine, PIC) chloride is reported. Correlation with the spectrum of imaginary parts of nonlinearity obtained by pump and probe techniques is discussed. Third order nonlinear susceptibility of PIC aggregates has been calculated supposing highest density packing attainable by Langmuir-Blodgett technique. The nonlinear figure-of-merit of aggregates was evaluated, which is intensity dependent due to exciton annihilation. Observed intensity and wavelength dependence of mixing efficiency is qualitatively explained in terms of absorption saturation, exciton annihilation, and subsequent generation of an excess diagonal disorder by vibrational energy accumulated in aggregates.