Third-order nonlinear susceptibilities of dye solutions determined by third-harmonic generation

The third-order nonlinear susceptibilities _xxx⁽³⁾ (–₃; ₁, ₁, ₁) versus concentration are determined for rhodamine 6G, fuchsin, and methylene blue in methanol. Third-harmonic generation of a modelocked Nd-glass laser is applied. The real and imaginary part of the nonlinear susceptibility are measured. A resonance enhancement due to absorption bands is observed.