2ND-HARMONIC GENERATION IN CENTROSYMMETRIC CRYSTALS OF CHIRAL MOLECULES

We demonstrate that for centrosymmetric structures of chiral molecules the interaction with circularly polarized light gives rise to nonzero second-order susceptibilities. It is ascribed to transitions that are both magnetic and electric dipole allowed. Experimental demonstration is given of second-harmonic generation from centrosymmetric crystals of R,S-N-acetyl valine (P21/c) using a fundamental wave having elliptic polarization in most parts of the trajectory through the crystal. These results demonstrate the existence of optical activity in the hyperpolarizability term, similarly to the well-known optical-rotation phenomena in the linear polarizability. © 1990 The American Physical Society.