Inge Asselberghs

Enhanced poling efficiency in highly thermal and photostable nonlinear optical chromophores

A series of nonlinear optical chromophores based on the highly thermal and photostable tricyanovinylidenediphenylaminobenzene (TCVDPA) was synthesized and their thermal and optical properties were investigated. Modification of the TCVDPA chromophore with bulky groups provides reduction of dipole–dipole interactions and thus great improvement of the macroscopic electro-optic (EO) response of the polymeric materials obtained by incorporating these derivatives as a guest at high loading in polysulfone. The best result was obtained with chromophore C5, bearing fluorinated aromatic substituents, which shows a doubling of the EO activity at 30 wt% (25 pm/V at 830 nm) compared with the pristine TCVDPA. The bulkier the chromophore, the lower the induced plasticization effect (as much as 50 °C difference on the Tg attenuation). Furthermore, all chromophores in this study possess good processability and exhibit high thermal decomposition temperatures (highest Td = 360 °C).

In situ Switching of the Second-Order Nonlinear Optical Response at the Molecular Level

We report on combined electrochemical and (non)linear optical experiments. The electrochemical experiments are conducted in solution and in situ monitored by hyper-Rayleigh-scattering. Also thin-films showed to be electrochemically-altered and in situ probed by second-harmonic generation.