All-optical sorting

The use of an optical lattice produced by means of a five-beam interference pattern to perform fractionation of co-streaming particles in microfluidic flows is discussed. It was found that when a flow of mixed particles passed through the lattice, selected particles strongly deflected from their original trajectories. The lattice suitable for sorting can be formed in a number of ways including the holographic technique. The use of optical lattices has potential for high continuous throughput at the size scale of cell sorting, where fractionation based upon size-dependent diffusivity cannot be used.