I-scan measurements of the nonlinear refraction and nonlinear absorption coefficients of some nanomaterials

We give the analytical expressions of the nonlinear transmittance of materials through an aperture in the far field with finite aperture size. The result can be used under the conditions of and . Based on this equation, the nonlinear refractive index coefficients of some nanomaterials from both the closed I-scan and Z-scan measurements at 800 nm and 1064 nm were extracted, respectively. The obtained values from I-scan measurements are comparable with those from the Z-scan measurements. The nonlinear absorptions of these materials were also studied by fulfilling the open I-scan and Z-scan measurements. The advantages of I-scan technology were discussed.