Hello Doanh,
We have an example of plasmonic simulations with a gold nanoparticle located at <a href=”https://optiwave.com/optifdtd-manuals/fdtd-nano-gold-particle/”>link</a>. This would make a good starting point for you. The difference is your example will have a second sphere set to air to give the hollow core.
The example uses a predefined Lorentz-Drude model for the gold. You will need to determine the coefficients for a Lorentz-Drude model of your Au-Cu2O. If you are using the 32-bit product you will need to manually determine those coefficients from a refractive index versus wavelength graph. If you have an active license and are using the latest product we have an automated fitting function that will do this for you provided you have the graph I just mentioned.
Scott