Subwavelength optical trapping and transporting using a Bloch mode.

Multi-functional optical manipulations, including optical trapping and transporting of subwavelength particles, are proposed using the Bloch modes in a dielectric photonic structure. We show that the Bloch modes in a periodic structure can generate a series of subwavelength trapping wells that are addressable by tuning the incident wavelength. This feature enables efficient optical trapping and transportation in a peristaltic way. Since we are using the guiding Bloch mode in a dielectric structure, rather than using plasmonic or dielectric resonant cavities, these operations are wide band and free from joule loss. The Bloch mode in a simple periodic dielectric structure provides a new platform for multi-functional optical operations and may find potential applications in nanophotonics and biomedicine.