Quadratic Electro-optic Measurements in Metal Nanoparticles within Glass: Effect of Particle-size and comparison with Iodine-doped Nonconjugated Conductive Polymers

Quadratic electro-optic effect in gold nanoparticles within glass has been measured for three different particle sizes, using field-induced birefringence at 633 nm wavelength. The measurements have been made using 4-cm long samples, with an ac field applied at 4 kHz, and with cross-polarized configuration. A quadratic dependence of the modulation on the applied field has been observed. Significant increases in the Kerr coefficient were observed for smaller particle sizes. Electroabsorption has also been measured. More detailed measurements are in progress. The particle-size dependence is consistent with the magnitudes of the exceptionally large Kerr coefficients reported for subnanometer-size metallic quantum dots created upon doping and charge-transfer involving the isolated double-bonds in nonconjugated conductive polymers.