Orbital rotation of multi-particle arrays in a dual-fiber optical trap

We propose a new and versatile way for optical orbital rotation of microscopic sized multi-particle arrays in a transversely misaligned dual-fiber optical trap. A PDMS(Polydimethylsiloxane) chip is designed to adjust the transverse offset distance between two fibers. It is possible to control the orbital rotation frequency and perimeter by varying the transverse offset distance without external influences. Experimental results show that there is a threshold value, beyond which the particles will rotate in a certain trajectory. The threshold values of the transverse offset required to initiate orbital rotation was found to be different for different number particle arrays. The proposed optical manipulation technique has been verified to be useful for cell sorting, optical binding and assembly of microstructures.