Time-Domain Simulati0ns of the Hyperpolarizability

The first hyperpolarizability of a quantum system is the fundamental building block of the nonlinear response of a material to high intensity light, which is the basis for a broad range of phenomena, devices, and applications. However, analytic solutions are rarely available. We present a simulation method based on the finite difference time-domain (FDTD) method which can determine the hyperpolarizablitiy of three-dimensional structures. The accuracy of the method is demonstrated on a clipped harmonic oscillator structure for which analytic solutions are known making it possible to determine the accuracy of the result.