Second Harmonic Generation enhancement by use of annular aperture arrays embedded into silver and filled by lithium Niobate

We propose and theoretically study a metallo-dielectric photonic crystal (MDPhC) based on metallic annular aperture arrays (AAA) associated to a nonlinear material (LiNbO3) for the second harmonic generation (SHG). An optimal structure design can be found thanks to the relations that link the geometrical parameters to the operating point namely the wavelength of the fundamental and SHG signals. A slow light phenomenon, which occurs at the cut-off frequency of the guided mode through the annular cavities, is at the origin of the SHG signal enhancement. The benefit of the AAA is demonstrated through a comparison with cylindrical aperture arrays. (C) 2010 Optical Society of America