Third-order nonlinear polarizabilities of a homologous series of symmetric cyanines

✍ Scribed by T. Johr; W. Werncke; M. Pfeiffer; A. Lau; L. Dähne

• Book ID: 103031356
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 428 KB
• Volume: 246
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(95)01133-x

✦ Synopsis

Third-order nonlinear polarizabilities of the homologous series of bis(dimethylamino)methine dyes (mono-, tri-, penta-, hepta-and non-amethine) were derived in the static frequency limit from dispersion curves measured by four-wave mixing techniques. Positive signs of the hyperpolarizabilities are obtained for mono-and trimethine: They are caused by positive contributions from ¢r electrons dominating the negative ~r electron contributions in the short chains. In the longer chains the hyperpolarizabilities exhibit negative signs and a strong enhancement (= -N 1 i) with increasing chain lengths due to the growing number (N) of contributing Ir electrons. A static hyperpolarizability of ---1 X 10 -33 esu which is obtained for the nonamethine, is the largest off-resonant experimental value reported for a polymethine dye.