New Organic Nonlinear Optical Verbenone-Based Triene Crystal for Terahertz Applications

New organic nonlinear optical verbenone-based triene crystals have been developed, investigated and compared to analogous isophorone-based triene crystals studied previously. The verbenone-based crystals show molecular conformation and crystal structure similar to the analogous isophorone-based crystals and therefore retain large macroscopic nonlinearity and high thermal stability. However, other physical properties are improved; for example, the solubility in acetonitrile is about 2.5 times higher, and the melting temperature is about 13 °C lower, which are an advantage for solution and melt crystal growth, respectively. The verbenone-based crystals of sufficient size for bulk nonlinear optical applications, that is, 5 × 4 × 1.5 mm 3, were successfully grown from acetonitrile solution by a slow evaporation method. Finally, terahertz (THz) absorption was measured in these crystals, and generation of THz waves was demonstrated.