Third-order nonlinear optical properties in soluble phthalocyanines with tert-butyl substituents

• Published in: Japanese Journal of Applied Physics 1991, Vol.30 (8), p.1715-1719
• Main Authors: HOSODA, M, WADA, T, YAMADA, A, GARITO, A. F, SASABE, H
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.30.1715

This paper reports on third-order nonlinear optical properties in various phthalocyanine compounds with tert -butyl peripheral substitution on each benzo ring at either the 2- or 3-position (tetra- tert -butyl-substituted isomer mixture). The third-order optical susceptibilities χ 1111 (3) (-3ω; ω, ω, ω)'s for the tetrakis( tert -butyl)phthalocyanine (TBPc) compounds were determined by optical third-harmonic generation measurements of spin-coated films at a wavelength of 1.907 µm. In each case, the third-order hyperpolarizability of the molecularly doped films is constant over the concentration of the TBPc's in polymethylmethacrylate. The χ (3) values of the TBPc's are smaller than those of unsubstituted phthalocyanines. In particular, χ (3) of tetrakis( tert -butyl)vanadylphthalocyanine (TBVOPc) is one order of magnitude smaller than that of VOPc. The origin of the large difference in χ (3) values is discussed in terms of molecular packing.