Indolic Squaraines as Two-Photon Absorbing Dyes in the Visible Region: X-ray Structure, Electrochemical, and Nonlinear Optical Characterization

Abstract

We present the design, synthesis, and structural characterization of short conjugation length squaraine structures having relevant two-photon absorption (TPA) performances in the 700−800 nm regime. We show in particular how it is possible to tune the TPA performances, only marginally affecting the linear absorption.