Determination of the lens transmittance of nonabsorbing media using the optical matrix method

摘要

The geometrical optics approximation is shown for the first time to be sufficient for determining the lens transparency in the Z-scan method for nonabsorbing media. The diffraction effects are taken into account in calculating the cross section of a focused Gaussian beam. With the use of the matrix method, the lens transparency of a Z-scan scheme is determined as a quantity inverse to the square of its normalized optical power. At a small phase incursion, the expressions for the lens transparency obtained by different methods coincide.