Chiral salts for nonlinear optics: Prospects and achievements

It is expected from theoretical models that, with comparable structure, anions will possess much higher intrinsic polarizabilities than neutral molecules. We suggest that noncentrosymmetric salts, obtained by associating large polarizable aromatic anions (ArS−,ArCO2−or anionic metal complexes) with chiral cations will be good candidates for 2nd order NLO properties. Along with theoretical results, preliminary Second Harmonic Generation experiments on chiral thiolates salts are presented and the possibilities of development of this concept are discussed.