عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this study, the nonlinear optical properties of a nematic liquid crystal doped with an azo dye were investigated. The magnitude and the sign refractive index and nonlinear absorption coefficient of a nematic liquid crystal doped with disperse-red-2- azo dye were measured by Z-scan techniques. The measurements were performed at 532 nm using a continues wave (CW) Nd: Yag laser.
We were looking for the effect of initial alignment on the nonlinearity of azo doped nematic liquid crystals (NLCs). The nonlinear refractive index and nonlinear absorption coefficient of homogeneous alignment sample is obtained in the order of 10-6 cm2/W and 10-1 cm/W, respectively with negative sign. The nonlinear refractive index and nonlinear absorption coefficient of homeotropic alignment sample is obtained in the order of 10-9 cm2/W and 10-5 cm/W, respectively with positive sign. Comparison of Z-san results shows the magnitudes of nonlinearity in homogeneous alignment samples are larger than homeotropic ones.
 I. Janossy, T. Kosa;” Influence of anthraquinone dyes on optical reorientation of nematic liquid crystals”; Optics letters Volume 17, Issue 17, (1992) 1183-1185.