Optically driven Mie particles in an evanescent field along a channeled waveguide

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Optical trapping and manipulation of microparticles are crucial for various scientific applications.
• Waveguide-based optical manipulation offers precise control over particle trajectories.

Purpose of the Study:

• To investigate the optical driving of Mie-scattering particles in a channeled waveguide's evanescent field.
• To demonstrate the trapping and longitudinal movement of both dielectric and metallic microparticles.

Main Methods:

• Utilizing a continuous-wave (cw) laser beam to generate an evanescent field within a channeled waveguide.
• Experimentally trapping polystyrene latex spheres (1-5 microm) and metallic spheres (gold, platinum) within this field.
• Achieving longitudinal manipulation of trapped particles along the waveguide channel.

Main Results:

• Polystyrene latex spheres were successfully trapped and moved at speeds up to 14 microm/s.
• Metallic spheres (0.5-microm gold, 1-microm platinum) were also laterally trapped and longitudinally driven.
• Demonstrated precise control over particle positioning and motion within the waveguide.

Conclusions:

• The evanescent field in a channeled waveguide is effective for optical manipulation of Mie-scattering particles.
• This technique allows for controlled transport of both dielectric and metallic microparticles.
• Potential applications in microfluidics, assembly, and sensing are suggested.