microfluidic + external force field (optical force)

Hi, everybody
I am a new user and just learned the tutorial of particle separation in microfluidics (www.comsol.com/model/red-blood-cell-separation-17013).

I am working on a problems that how the particle motion will be deviated by an external force field, may I know how to do the modification from that tutorial?

This force is generated from an external electromagnetic wave, so called optical force. If I want to further include the RF module and do the whole simulation, are there any samples I can follow please? thank you!