Soda-lime silicate (SLS) glasses were thermally poled at 230°C-280°C with dc voltages up to 2kV applied to induce a second-order optical nonlinearity. Accompanying structural modifications to the thermally poled SLS glasses were investigated with scanning electron microscopy. On the cathode surface, sodium metasilicate crystals were formed through the reduction of migrating sodium ions at the cathode. At the anode, intense phase separation occurred within several micrometers beneath the anode surface during the thermal poling process. These structural modifications are attributed to the electric field enhancement effect. The second-order nonlinearity induced in such poled samples was found to still be present after a long period of high-temperature annealing, perhaps mainly due to a hindering effect from the phase separation and/or accumulated calcium ions to the recombination of space charges.
© 2006 Optical Society of America
Original Manuscript: April 14, 2006
Revised Manuscript: August 1, 2006
Manuscript Accepted: August 6, 2006
Honglin An and Simon Fleming, "Second-order optical nonlinearity and accompanying near-surface structural modifications in thermally poled soda-lime silicate glasses," J. Opt. Soc. Am. B 23, 2303-2309 (2006)