Primary Study on a New Kind of Second-Order Nonlinear Optical Material - m-Hydroxybenzoic Acid

A new kind of second-order nonlinear optical (NLO) material - m-hydroxybenzoic acid (HBA) was reported in this paper. Primary study results revealed that it had a relatively strong nonlinearity, its powder SHG effect was 12 times that of KDP. The solid cut-off wavelength λcut-off(350 nm) is very short compared to other organic second-order NLO materials. The experimental results also showed that HBA had a high laser damage threshold and good characteristic thermal stability. Furthermore, We calculated its second-order nonlinear hyperpolarizability β and analyzed the microscopic nonlinear properties, and found that the hydroxyl group could improve β obviously while the hydroxyl multisubstitution could hardly contribute to β values.