Simulations of near-field excitation and trapping for integrated near-field optical microfluidic devices

Simulations of near-field excitation and trapping at 100 nm apertures were conducted to aid design of an integrated near-field optical device for detection and manipulation of molecules in fluidic microchannels. The simulations indicate that optical trapping will occur at nearfield aperture edges, and if plane-polarized light is used the trapping edge can be selective. By changing the plane of polarization the position of the trap can be rotated. The nearfield apertures have been fabricated inside microchannels using a novel batch micromachining process. The process consists of patterning micron size holes in a silicon nitride membrane, which are then reduced in size through the redeposition of silicon nitride thin films. Nanoholes down to 100 nm in diameter have been fabricated.