Solvent effects on the nonlinear optical response of a potentiometric biological imaging dye

摘要

To understand the electronic mechanisms for the electric-field sensitive second-harmonic response of di-8-442[6-(dioetylamino)-2-naphthalenyllethneyl)-1-(3-sulfopropyl) pryridinium inner salt in biological membranes, we have measured its nonlinear optical hyperpolarizability using a combination of hyper-Rayleigh scattering and linear optical properties in solvent environments of various polarity. Changes in the first hyperpolarizabilities are discussed by modeling experimental inputs from the solvatochromic effect in linear absorption and appropriate dispersion relations near the two-photon resonance. We find that both frequency-dependent and frequency-independent effects make significant contributions to the response, and the strongest response is on the low-energy side of the two-photon resonance, while the weakest response is on the high-energy side of the two-photon resonance. (C) 2007 Optical Society of America