A comprehensive linear and nonlinear study on a fluorescent stain

Abstract

The optical properties, linear and nonlinear, for Leishman stain are studied in ethanol and chloroform over a wide spectral region. The stain consists of two components: Methylene blue (MB) and Eosin (E). The low intensity optical measurements, linear regime, show the absorption and emission characteristics of the E and the MB components in ethanol and only the MB component in chloroform. Under the influence of optical intensity less than 15[Formula: see text]MW/m2, the stain shows nonlinear absorption characteristics at excitation wavelengths 532[Formula: see text]nm and 650[Formula: see text]nm only. The nonlinear absorption coefficients of the solutions are in 1–12.4 [Formula: see text][Formula: see text] cm/W range in both solvents. Leishman stain solutions in ethanol and chloroform have a strong thermal nonlinearity with a negative index of refraction over the entire visible region. The value of the nonlinear refractive index ([Formula: see text]) of Leishman stain in both solvents increases as the wavelength of the excitation radiation increases. The value of [Formula: see text] of the solutions is in the range of about 2–46 [Formula: see text][Formula: see text][Formula: see text]cm2/W. As an example of the optoelectronic applications, the stain shows excellent properties of an energy spreading optical limiter.