Nonlinear complex susceptibility of cresyl violet solution measured with a dynamic grating method

The absolute square of the complex nonlinear third-order susceptibility χ₃ was investigated by measuring the self-diffraction efficiency η of a transient laser-induced population grating. Cresyl violet in methanol was examined in the wavelength range of S₀ ground state absorption. For this dye, the real and imaginary parts of χ₃ were separated by additional determination of the nonlinear absorption. Both parts of χ₃ are plotted between 570 and 625 nm and their relation to each other was examined by using a Kramers-Kronig formula