High Sensitive Measurement of Absorption Coefficient and Optical   Nonlinearities with a Single Experimental Setup
  Accurate knowledge of absorption coefficient of a sample is a prerequisite for measuring the third order optical nonlinearity of materials, which could become a serious limitation for unknown samples. We introduce a new method, which measures both the absorption coefficient and the third order optical nonlinearity of materials with high sensitivity in a single experimental setup. We use a dual-beam pump-probe experiment under different conditions to achieve this goal. We also demonstrate a counterintuitive coupling of the non-interacting probe-beam with the pump-beam in pump-probe z-scan experiment. 
S. Abbas Hosseini, A. Sharan, D. Goswami