A comprehensive linear and nonlinear study on a fluorescent stain.

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 MW/m², the stain shows nonlinear absorption characteristics at excitation wavelengths 532 nm and 650 nm only. The nonlinear absorption coefficients of the solutions are in 1–12.4 × 1 0 − 3 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 ( n 2 ) of Leishman stain in both solvents increases as the wavelength of the excitation radiation increases. The value of n 2 of the solutions is in the range of about 2–46 × 1 0 − 7 cm²/W. As an example of the optoelectronic applications, the stain shows excellent properties of an energy spreading optical limiter. [ABSTRACT FROM AUTHOR]