摘要 |
<p>Optically non-linear materials suitable upon repeated Langmuir-Blodgett dipping for forming Z-type (head-to-tail) films for second harmonic generation include hemicyanine dyes which are very unsymmetrical, i.e. which have hydrophobic substituents differing in size by at least 4 carbon atoms, each end of a hydrophilic chromophore. A suitable dye is E-N-octadecyl-4-[2-(4-dibutylaminophenyl)ethenyl]quinolinium iodide.</p> |