Influence of microscopic parameters of chiral molecules on the first-order hyperpolarizability

One-electron model is chosen to analyze the second harmonic response of an organic inclusion complex - urea l-malic acid (ULMA). ULMA has broad transparent region and large nonlinear optical coefficient and damage threshold. Based on the ULMA crystal structure, the model parameters are determined using the unit cell parameters. Numerical results show that the contribution of electric-field to the first-order hyperpolarizability β is larger than that of magnetic-field but the contribution of magnetic-field is important and cannot be neglected. Modeling parameters pitch ξ and radius ρ are found to be involved in the position of peak of β. The peak position of β undergoes red-shift with increasing of ρ and blue-shift with the increasing of ξ. It suggests that the expected nonlinear optical response of a chiral molecule can be obtained through molecular modification to adjust ξ and ρ. Therefore, a chiral molecule may be a favorable host to afford organic inclusion complex with superb nonlinear optical properties.