New nonlinear-optical organic crystal: 4-dimethyl-aminobenzaldehyde- 4-nitrophenyl-hydrazone

Single crystals of 4-dimethylaminobenzaldehyde-4-nitrophenylhydrazone were grown from solution. We determined their linear-optical (absorption and refractive indices) as well as their nonlinear-optical properties. From the highest nonlinear-optical coefficient $d_{12}=270$ pm/V at $\mathrm{\lambda }=1.542$ µm we determine an effective nonlinear-optical coefficient $d_{\mathrm{eff}}⩾150$ pm/V for phase-matched frequency doubling that is, to the best of our knowledge, the largest reported phase-matchable coefficient. The nonlinear-optical properties are discussed in terms of the crystal structure and the molecular hyperpolarizabilities. In addition, the phase-matching configurations for second-harmonic generation and optic parametric oscillation are derived.