Toward an Organic Pockels Cell Operating in the Visible
Timothy M. Pritchett, Robert C. Hoffman, Joshua A. Orlicki, Jan Andzelm, Adam M. Rawlett, Matthew C. Davis, Stephen Fallis, Andrew P. Chafin, Geoffrey A. Lindsay, Dong Park and Warren N. Herman
A novel dialkylamino-phenylethynyl-benzonitrile dye attached to polyimide was recently synthesized. The new side-chain polymer exhibits an absorption maximum at ∼395 nm and is essentially transparent for wavelengths greater than about 470 nm.A2.7-μmfilm of the polymer was poled and the electro-optic activity r33 of the poled thin film measured at 532 nm using the Teng-Man technique, yielding a value of 12 ± 2 pm/V. Various 700-μm-thick plaques of polymethylmethacrylate (PMMA) doped with Disperse Red 1 dye (DR1) in various concentrations were fabricated and poled. Birefringence is observed in the poled regions of the plaques, and second-harmonic generation (SHG) Maker fringe data at 1319 nm demonstrates the existence of significant ordering of the DR1 chromophores as a result of the poling process. The r33-value of the resulting poled thick samples, determined from an analysis of the Maker fringe data, is estimated to be 6.1 pm/V at 810 nm, which compares favorably with the highest r33 observed in a DR1-copolymer system (7.5 pm/V). The use of micro-compounding in processing the doped polymer appears to inhibit aggregation of dye molecules, leading to more efficient poling and a higher resulting EO activity at a given dye loading.
Keywords: Electro-optic polymer, Pockels cell, electric field poling, bulk-sample poling, optical switching, terahertz generation.