Photonic Applications With the Organic Nonlinear Optical Crystal DAST

We review the recent progress in the development of photonic applications based on the organic crystal 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium tosylate (DAST). DAST is an organic salt with an extremely high nonlinear optical susceptibility chi((2)) (-2 omega, omega, omega) = 580 +/- 30 pm/V at 1.54 mu m, a high electrooptic figure of merit n(3)r = 455 +/- 80 pm/V at 1.54 mu m, as well as a low dielectric constant epsilon = 5.2. DAST is, therefore, very attractive for high-speed optical modulators and field detectors, as well as for frequency conversion and the generation of terahertz waves. Several techniques to microscopically structure this material have been developed recently; including modified photolithography, photobleaching, femtosecond laser ablation, graphoepitaxial growth, ion implantation, and direct electron-beam structuring, which open new perspectives of using this exceptional material for high-speed very-large-scale integrated photonics.