Here we show how to simulate plane wave scattering on a sphere. FDTD unit of length is 0.1 micron Scattering on sphere If your unit of length is 0.1 micron, useĮmMedium au =GetAu ( 0.1 ) // au is gold. Returns approximation for gold used above for default FDTD length unit 1 micron. There are ready approximations for some media (gold, silver, silicon, tungsten etc.) in EMTL.Ĭorresponding functions are collected in photonic/opt_data.h.ĮmMedium au =GetAu ( ) // au is gold. Therefore argument of function calibrate should be inverse light speed (second / micron).

Since, FDTD unit of time is time necessary for light to cover one micron.

In our example FDTD unit of length is 1 micron. This function multiplies, , (also and ) by its argument. To change dimension for considered parameters, we use function calibrate. In our code this dimension is assumed to be radians / FDTD unit of time. In this work dimension of parameters, is radian / second. Parameters for Drude and Lorentz constructors are, , and. Sometimes nonzero value helps to make better fitting for given while conventional Drude and Lorentz form fails (see details here). Zero values corresponds to conventional Drude and Lorentz form.

Where is permitivitty at infinite frequency, and, ,, are fitting coefficients that do not necessary have a physical meaning. Instead, it can be approximated using multiple Drude or Lorentz terms in the form: Unlike frequency domain methods, the dielectric permittivity of dispersive materials in tabular form cannot be directly substituted into the FDTD scheme. Constructor arguments are dielectric permittivity, conductivity, magnetic permeability and magnetic losses.

Fdtd solutions tutorial