Investigating the Second Harmonic Generation in One-Dimensional Multi-layer Structure Consisting of Polar Ferroelectric Called 𝐋𝐢𝐓𝐚𝐎𝟑 Using the Transfer Matrix Method

Abstract

The transfer matrix method is widely used to calculate the electromagnetic waves dispersion. In this paper, we have investigated the second harmonic generation in a one-dimensional structure including LiTaO3 ferroelectric. Using the transfer matrix method, we obtain the second harmonic efficiency. In this article, in the structure of nonlinear photonic crystals, the linear and nonlinear optical parameters are changed periodically, which causes the second harmonic conversion efficiency to be several times greater than the conversion efficiency of a nonlinear structure based on conventional quasi-phase matching (QPM). The reason for this is that in the system discussed in this paper, the presence of effects of band gap edges causes the density of states of the electromagnetic fields is increased, the group speed of the electromagnetic waves is decreased (as a result, the interaction time is increased) and local field is boosted. As a result of these three factors, the nonlinear optical interaction is effectively strengthened.