Most nonlinear experiments using hollow-core PCF rely on the intrinsic third-order nonlinearity of the filling gas, which has vanishingly small values of second-order susceptibility χ(2). If however a dc electric field is applied, the centrosymmetry can be broken and an effective χ(2) induced. This process has been studied in conventional step-index fibres, for example by direct electric field poling [Kazansky (1997)]. In this project, we have demonstrated electric field-induced second harmonic generation (EFISH) using external electrodes to induce a second-order nonlinearity in gas-filled HC-PCF.
This project is an on-going collaboration with Prof. Jean-Michel Menard at the University of Ottawa, supported by the Max Planck-uOttawa Centre for Extreme and Quantum Photonics.