Silver dispersed in tetraethyl orthosilicate (TEOS) matrix are promising candidate materials for photonic device applications such as optical switching, optical limiting, self-focusing and defocusing, and optical data processing. A well-known single Z-scan technique is employed to determine third-order nonlinear optical properties of nonlinear optical materials. Z-scan is a simple experimental technique to measure intensity dependent nonlinear susceptibilities of third-order nonlinear optical materials. It was originally introduced by Sheik Bahae et al. In this technique, the sample is translated in the z-direction along the axis of a focused Gaussian beam, and the far field intensity is measured as function of sample position. Consequently, increases and decreases in the maximum intensity incident on the sample produce wavefront distortions created by nonlinear optical effects. This is a simple and sensitive single beam technique to measure the sign and magnitude of both real and imaginary part of the third order nonlinear susceptibility χ⁽³⁾ of nonlinear optical materials. A laser beam propagating through a nonlinear medium will experience both amplitude and phase variations. If transmitted light is measured through an aperture, placed in the far field with respect to focal region, the technique is called closed aperture z-scan experiment. By varying the aperture in front of the detector, one makes the z-scan transmittance more or less sensitive to either the real or imaginary parts of the nonlinear response of the material, i. e., nonlinear refractive index and nonlinear absorption, respectively.

Z-scan, Photonics, Nonlinear Optics, Nonlinear Optical Material, Nonlinear Absorption and Refraction