H. J. Ravindra

Superior characteristics of organic chalcone single crystals as efficient nonlinear optical material

High-quality biaxial single crystals of chalcone derivatives were grown by solution growth technique. Their molecular structures were designed to possess large second-order nonlinearities by choosing proper donor/acceptor groups while retaining a high transparency in the visible and infrared spectral regions. The second-order nonlinear optical coefficients, determined by applying the Maker fringe technique, were found to be much larger than those of LiB3O5, KTiOPO4, KH2PO4, and urea. The advantages, such as easy synthesis and crystal growth, low cutoff wavelength ( 7.2GW∕cm2), make these organic crystals promising for efficient frequency doubling.

1-(4-Aminophenyl)-3-(3,4,5-trimethoxyphenyl)prop-2-en-1-one–1-(4-aminophenyl)-3-(3-bromo-4,5-trimethoxyphenyl)prop-2-en-1-one (0.972/0.028)

In the title cocrystal, 0.972(C18H19NO4).0.028(C17H16BrNO3), which arose from an impure starting material, all the atoms are overlapped except for one OMe group and the Br atom. The dihedral angle between the benzene ring mean planes is 18.20 (13)°. A weak N—H⋯O hydrogen bond helps to establish the non-centrosymmetric crystal packing.

Design of new organic single crystals for ultrafast optical applications

A new chalcone crystal designed with suitable functional groups exhibits ultrafast response (<90 fs) and very large two-photon absorption (2PA) (β > 8 ×10² cm/GW). Its low intensity threshold (<4 MW/cm²) for 2PA and high damage resistance (>8 GW/cm²) are quite interesting for 2PA-based optical limiting.