Nonlinear optical properties of a dithiooxamide determined by single beam techniques

The third-order nonlinear optical properties of an inorganic compound (NH2CSCSNH2) were studied by means of single beam transmission techniques, using a continuous-wave (CW) He-Ne laser beam with a wavelength of 632.8 nm a laser power of input 6.6 mW. The magnitude and sign of the third-order nonlinear refractive index (n(2)) of a saturated solution of this material in water were determined by use of both the closed-aperture z-scan and the Moire deflectrometry techniques. The negative sign obtained indicated that there is a self-defocusing effect in the sample. The nonlinear refractive index n(2) and the change in the refractive index (Delta n) were in the order of 10(-7) cm(2) W-1 and 10(-5), respectively, both having a negative sign. The nonlinear absorption coefficient beta was calculated by the use of the open-aperture z-scan technique to be -1.8 x 10(-3) cm W-1. (C) 2007 Elsevier B.V. All rights reserved.