Broadband Nonlinearity of Trypan Blue Dye for Optoelectronic Applications

Abstract

This work presents detailed investigation on the linear absorption, emission, and nonlinear absorption and refraction of the organic dye Trypan Blue (TB) in two polar solvents water and ethanol. The nonlinear characterization was carried out by utilizing the z-scan technique with four excitation wavelengths 405, 473, 532, and 650 nm. The linear study indicates minor effects of the solvent and the major relaxation processes of the dye are non-radiative except a very small portion appears in the form of low fluorescence at the red edge of the visible region. In an intensity range (1.8-6.2 MW/m²), the TB dye does not show any nonlinear absorption properties. However, TB shows significant defocusing nonlinearity over the whole visible region. The dye shows high reliability properties of optical limiting and possibility of active optical control. The results of this study can open new insight in the TB dye usage in several photonic and optoelectronic applications.