Optical trapping SiO2 nanoparticles based on liquid-core metal-cladding waveguide

Because of the demand for low-cost optical trapping small particles without directly touching in subwavelength volume, a liquid-core metal-cladding waveguide (LCMW) structure was put forward, and it retained all the merits of MCW, such as free space coupling, a large detection area, and polarization independence. LCMW was used for optical trapping of SiO2 colloid particles. The reflectivity of the guiding layer was monitored to investigate the factors influencing the self-assembly speed of the SiO2 particles (time for the reflectivity to reach a stable state). The results demonstrate that a smaller ultimate reflectivity of light, longer light-off time, or a higher sample refractive index increases the required optical trapping time for the SiO2 colloid particles to reach a stable state.