Picosecond measurement of the nonlinear refractive index of new salts of carboxylate anions with chiral ammonium cations

The third order nonlinear optical properties of novel carboxylate anions with chiral amines and ammonium cations have been studied by a new alternative of the classical z -scan technique with picosecond laser pulses (pulse duration of 30 ps at 1064 nm wavelength). The materials do not present linear and nonlinear (two-photon) absorptions at the wavelength and the intensities used for the experiments. The non-resonant molecular second order hyperpolarizability γ obtained can reach 4.4 × 10 ⁻⁴⁸ SI. These values are two and three orders of magnitude larger than those CS ₂ and of C ₆H ₆ respectively.