Three Dimensional Optical Twisters-driven Helically-Stacked Multi-layered Microrotors


The use of structured light fields for controlled rotation and orientation of microparticles is receiving considerable attention in micro fluidics, and cell biology, due to the fact that it eliminates most of the inherent limitations of other existing approaches. We report here the generation of optical traps within individually tunable three dimensional (3D) helical intensity patterns by the designed superposition of phase engineered multiple plane waves using a programmable spatial light modulator (SLM)-assisted dynamically reconfigurable approach. We demonstrate tunable helically stacked multi-layered microrotors realized in vortex-embedded 3D optical twister patterns. Intensity-tunable annular irradiance profiles with higher order vortex are generated as well as simultaneously unfolded by phase-engineered multiple plane wave interference. In the individually-tunable 3D helical bright arms of these unfolded vortex-embedded structures, 2µm silica beads are optically trapped as spiraling multilayered handles of multi-armed microrotors. We also present our observation on helical 3D stacking of micro-particles in these longitudinally gyrating multi-armed rotor traps. Moreover, the presented in-plane parallel actuation of multiple rows of microrotors with controllable sense of rotation, points to their potential applications for advanced individually addressable helically stacked bio-motors, reconfigurable multiple micro-pumps, tunable micro-stirrers and tailored particle sorting micromachines etc.

Contact details: 

Prof. Joby Joseph and Jolly Xavier

Department of Physics