In-plane poling characterization of organic electro-optical polymer

The purpose of this work is to investigate the in-plane poling technique and to make a comparison with the corona poling technique. To this end we chose as a test material a well known guest-host system, disperse red 1 in polymethyl methacrilate. The second harmonic generation and the order parameter, determined by means of polarized absorption spectroscopy, have been monitored to test the effectiveness of the poling. We found out that the shorter the gap distance between the electrodes, the higher is the maximum achievable value of the applied voltage, without occurrence of the electrical discharge, this increase in the electrical field enhances the poling efficiency thus enlarging the possibility to employ this configuration in electro-optical devices, such as Mach-Zehnder modulators. The use of quartz slide instead of BK7 and the careful tuning of the coplanar-electrode distance allowed to reach a high poling efficiency, yielding a nonlinear coefficient upto 25 pm/V while a value not higher than 8 pm/V was obtained with a traditional corona poling.