The promise of nanotechnology won't be realized unless nanometer-scale structures can be assembled together inexpensively into a working system. The goal of this proposal is to develop and test a revolutionary tool that uses light-pressure forces to rapidly assemble complex nanosystems comprised of structures ranging in size from ~10nm to 1mm. Intellectual Merit: We plan to develop a tool to assemble a nanosystem layer-by-layer using light pressure forces to produce multiple, independent optical traps for organizing simultaneously tens of thousands of nanometer-scale structures within each layer. The optical traps will be produced either by rapidly scanning a laser beam from one trap location to the next, relying on the viscosity of the medium to stabilize the position until the trap is refreshed, or by generating a hologram, where multiple optical traps are created simultaneously by controlling the intensity and phase profile of the beam using a spatial light modulator. Either way, the tool will have to compensate in real-time for the scattering environment of the trap during the layer-by-layer assembly. Therefore, there are two elements at the core of this proposal: 1. the efficient simulation of the dynamic electromagnetic environment of the trap, which is used to predict in real-time the required intensity and phase profiles for the laser; and 2. the concomitant synthesis through adaptive optics of the trap.
Broader Impact: Aside from the development of a new tool for nanoscale manufacturing that assembles nanometer-scale objects using light, there is a broader impact of this work derived from the nature of the testbeds we choose to explore, which can only be fabricated through optical manipulation. In particular, we plan to contribute to the understanding of self-assembly and locomotion in living cells through our work on "artificial cytoskeletons," by using optical tweezers to control the assembly of the molecular networks that form the cell's structure. Moreover, our work will affect supra-molecular chemistry in a fundamental way by augmenting the weak noncovalent bonds that form soft-condensed matter systems such as proteins, biological membranes and DNA with "optical binding" forces. By using optical binding forces in conjunction with supra-molecular forces, we hope to gain insight into the structure of the supra-molecular aggregates and their interactions. In addition, significant educational efforts are planned in the form of monthly seminars, innovative new interdisciplinary courses, and extensive involvement of undergraduate students in the research.
