Configurationally locked, phenolic polyene organic crystal 2-{3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene}malononitrile: linear and nonlinear optical properties

Abstract

We show that the organic polyene crystal 2-{3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene}malononitrile (OH1) is a new material with excellent nonlinear optical and electro-optical properties. The principal refractive indices and the absorption constants have been determined over a broad wavelength range from 0.6to2.2 μm. OH1 shows a large birefringence of Δn>0.55 and a low absorption of α<1 cm−1 in a large wavelength range between 800 and 1400 nm. Furthermore, the nonlinear optical tensor elements d333=120 ± 10 pm/V, d223=13 ± 2 pm/V, and d322=8.5 ± 2 pm/V have been determined by the Maker-fringe technique at the fundamental wavelength of 1.9 μm. The electro-optic coefficients r333, r223, and r113 have been measured at the wavelengths of 633, 785, 1064, and 1319 nm, and it is shown that the dispersion can be described by a one-oscillator model. OH1 is a promising material for nonlinear optical and electro-optical applications due to the large nonlinear coefficient d333, the large electro-optic coefficient r333=109 ± 4 pm/V at 632.8 nm, the favorable crystal growth properties, as well as the orthorhombic crystal symmetry (point group mm2), which renders crystal preparation and orientation much simpler than in most organic nonlinear optical crystals.