Third-order nonlinearity and optical limiting studies in phosphorus (V) porphyrins with charge transfer states

Abstract

Enhancement in the third-order nonlinearity χ(3), nonlinear absorption and optical limiting threshold with the introduction of charge transfer (CT) states are observed in a new class of azoarene phosphorus (V) porphyrins. Introduction of axial azoarene groups into the phosphorus porphyrin structure led to a rise in the measured 〈γ〉 values. Faster intersystem crossing from CT states to triplet and excited state absorption from the triplet states contribute to the enhancement of nonlinear absorption thereby reducing the optical limiting threshold by a factor of 2. © 2002 Elsevier Science B.V. All rights reserved.