Poling of glass waveguides by a metal-induced χ(3) enhancement

While the perspectives of making 2nd-order nonlinearities in optical glasses are exciting, present poling techniques are still inadequate. When inducing a permanent field E_dc in the glass, the effective 2nd-order susceptibility χ⁽²⁾=3χ⁽³⁾E_dc has been limited by the small intrinsic value of χ⁽³⁾. Here we demonstrate that metal nanoclusters are an attractive means to enhance the χ⁽³⁾ value. In combination with a built-in dc-field in channel waveguides, effective χ⁽²⁾ values of more than 14 pm/V are obtained.