Multipath Trapping Dynamics of Nanoparticles towards an Integrated Silicon Slot Waveguide

We study the trapping dynamics of a nanoparticle near a silicon slot waveguide. It is shown for the first time that a nanoparticle can go along different paths before it becomes trapped. The optical forces originating from different parts of an optical mode compete with each other during particle transport, forming a complicated particle trajectory and particularly a critical area where particle transport becomes unstable. Brownian motion is simulated for 50-nm and 100-nm nanoparticles, and the induced instability is analyzed.