Near field/Far Field of scatered light from a nanoparticle

Hi,I am simulating in Comsol 4.2.

In my simulation domain ,2 micrometer by 2 micrometer,the upper portion is air and the lower surface is glass.A nanoparticle of 300 nm is placed at the interface(halfway in my simulation domain).I want to analyse the fields(near and far field) after light been incident from the top surface of my simulation domain and scattered by the particle.
I am using scattered boundary conditions for my simulation domain boundaries (i dont kno if that is correct)

I want to know how to analyse the far field here.I will be looking forward to the detailed steps.I also want to know if my boundary conditions are correct.I am using 2D model

I will be waiting eagerly for the kind reply and the solution

Regards