Robust increase of the optical forces in waveguide-based optical tweezers using V-groove structure

Abstract

Waveguide-based optical tweezers have significant advantages for particle trapping and transporting in optofluidic chips due to their simple fabrication process. However, for effective trapping of nanoparticles, a high-power input field should be applied, which limits their applications. Here, we numerically show that a silicon-on-insulator-based V-groove waveguide has a much higher capability to trap nanoparticles compared with the traditional waveguides. According to the calculations, the trapping force exerted by the V-groove waveguide to a 5 nm radius nanoparticle can be 14 times greater than that of the strip waveguide. The scattering force is five times larger in the same conditions. This structure would be useful to be integrated into a lab-on-a-chip system to form a particle delivery and analysis device.