Fitting Complex Metal Dielectric Functions with Differential Evolution Method

The real and imaginary part of dielectric permittivity of the metals is important to simulate the optical properties of metal films and nanoparticles. Permittivity data is obtained experimentally by ellipsometry and is fitted with analytical models. The most common model for fitting experimental data is with Drude-Lorentz model shown below. $$\epsilon(\omega)=1-\frac{f_1\omega_p^2}{(\omega^2+i\Gamma_1\omega)}+\sum_{j=2}^{n}\frac{f_j\omega_p^2}{(\omega_{o,j}^2-\omega^2-i\Gamma_j\omega)}$$ The first term is Read More …

DDSCAT on amazon EC2

Amazon provides high performance computing capabilities through their EC2 service. You can find more information here They provide a 750 hr free instance with their a free-tier program. If you want more resources, you can pay for it. See the pricing, pricing seem very reasonable. I wanted to see how easy it was to install Read More …