Nonlinear refractive index measurements using time-resolved digital holography.

In this Letter, a novel method to evaluate nonlinear refractive index using time-resolved digital holographic microscopy is introduced. To demonstrate the viability of the method, cross-correlative nonlinear refractive index values for sapphire are measured experimentally: 2.75·10-20  m2/W at 1030 nm and 4.10·10-20    m2/W 515 nm wavelengths. The obtained results for sapphire are compared to those available in literature obtained by other methods.