Synthesis of new squaraine dyes for optical switches

This work describes the synthesis of new, highly soluble squaraine dyes, which have absorption maxima over 900 nm in solution. The absorption spectra of their spin-coated films show broad absorption bands, which are caused by aggregation phenomena. The absorption bands in the solid phase are red-shifted compared to those in solution. Because of these characteristics and nonlinear optical data which were obtained by Z-scan measurements, the new substances are principally useful for optical switches. (C) 2003 Elsevier Science Ltd. All rights reserved.