On-chip Periodic Arrays of Optical Traps Based on the Superposition of Guided Modes in Silicon Waveguides

Summary form only given. Since the pioneering work of Kawata and Tani, photonic waveguides have long been regarded as efficient optical conveyor belts for potential lab-on-a-chip applications. Indeed, near-field optical forces arising at the surface of such waveguides lead to efficient on-chip guided propulsion of micro- and even nanoparticles , as well as cells and bacteria in liquid solutions. However, achieving stable and precisely controlled optical trapping of particles at the surface of a waveguide has been made possible only recently, and even then, it still requires complex photonic electro-optic tools to produce and handle on-chip standing waves. In this work, we investigate a different and simpler way to tune by all -optical means the distribution of near fi eld optical forces along photonic waveguides [5]. More especially, we demonstrate how the co -propagation of several modes in a SOI nanobeam waveguide affects the trajectory of the propelled microbeads. The influence of the waveguide width, the laser power, or the wavelength is studied.