Abstract

Surface Second Harmonic Generation (SHG) is a second order nonlinear process that can only be observed in materials with broken inversion symmetry. However, due to the discontinuity of the medium and the large electric field gradient at a surfaces, the inversion is broken and SHG can be generated there, too [1]. A.Pakhamov and et al [2] theoretically studied the surface SHG from ultrathin stacks of TiO₂/SiO₂. There many surfaces contribute to SHG in a subwavelength arrangement. They have predicted SHG enhancement from superimposing the signals from each surfaces with transfer matrix method.

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