Investigation of thickness and concentration effects on the nonlinear optical properties of yellow disperse doped PMMA

Nonlinear optical properties of yellow disperse 211 doped polymethyl-methacrylate (PMMA) solution in acetone is studied experimentally employing different optical techniques. The effects of thickness of sample as well as its concentration effects are investigated in detail. Experiments are performed using the second harmonic of a continuous Nd-Yag laser beam at 532 nm wavelength and 20 mW power. The effect of nonlinear refractive index of liquid films is obtained by measuring the profile of propagated beam through the samples and their nonlinear refractive index is found to be negative. The optical limiting behavior of samples is investigated by measuring the samples transmission. The third order nonlinearity ?3 is measured using Z-scan data. The nonlinear absorption coefficient is calculated using open aperture Z-scan data while its nonlinear refractive index is measured using the closed aperture Zscan data. Real and imaginary parts of the third-order nonlinear optical susceptibility ?3 are changed significantly with thickness and concentration.