Simultaneous Trapping and Manipulation of Micro-Specimens Using an All-Dielectric One-Dimensional Photonic Crystal

We demonstrate a platform where optical evanescent vortex has been realized by focusing a laser beam with orbital angular momentum (OAM) onto an all-dielectric one-dimensional photonic crystal (1DPC). This platform can simultaneously trap and manipulate various micro-scale specimens (i.e., polymer microsphere, inorganic microwire, yeast cells and Escherichia coli cells). The working principle lies in the low loss of the excited Bloch surface waves (BSWs) that propagate on the dielectric 1DPC and form a virtual probe for trapping the specimens. The OAM encoded by the BSWs will then simultaneously manipulate the specimens, such as inducing the rotation or orbital motion. Both experimental and simulation results verify that the capability of this new platform is due to the two kinds of optical force induced by the BSWs, which presents a different mechanism from that by the commonly optical electric-field vortex. Optical trapping or manipulation of micro & nano specimens play important roles in physics, life and materials sciences, thus, this new platform will find applications in microscale assembly, cell-cell interaction, bioprinting and biosensing research, and also expand our understanding of the physics interaction between vector beam and BSWs.