Being able to reach into the microscopic world dexterously and non-invasively at many points at once, being able to cut, assemble and transform with nanometer precision and sub-micrometer resolution, and being able to do all these things with a single instrument promises revolutionary advances across many disciplines. The foregoing sections highlight just a few of these advances. In particular, wavefront engineering provides a straightforward means to create large numbers of optical traps in arbitrary three-dimensional configurations, to move them freely and independently in three dimensions, and to transform them into optical vortices, optical bottles, Bessel traps, and a host of other all-optical tools.
As tools for biology, multifunctional optical traps will facilitate new approaches to cell sorting, macromolecular purification, intracellular surgery, embryonic testing, highly parallel drug screening among a great many other possibilities. The same tools have immediate applications for organizing mesoscopic matter into heterogeneous hierarchically structured three-dimensional functional systems, such as photonic circuit elements, integrated sensor arrays, and high-density data storage devices. Combining this organizational capability with optical-tweezer-based spatially-resolved photochemistry suggests bright prospects for optically assembling new materials and devices with features ranging from nanometers to millimeters and beyond.
In micromechanics and microfluidics, appropriately sculpted wavefronts of light can easily control motions and flows on length scales that have challenged other technologies. In so doing, optical micromachines should help to hasten the adoption of lab-on-a-chip devices for diagnostics, sensing, testing, pathology, and drug discovery. The same wavefront-shaping techniques can sort and purify materials in these tiny flows and direct them toward further stages of purification and analysis. Optical testing and manufacturing thus could be highly integrated, with a single instrument providing flow, sorting, organization, synthesis, and assembly.
In all of these areas, the emerging generation of optical manipulation tools should help to bridge the chasm between our macroscopic world and applications based on the physics, chemistry, and biology of microscopic systems.