arXiv subjects
Publications and source records attributed to David S. Bradshaw.
In response to arXiv:1506.07423v1 we discuss the authors work, and our own, on proposed schemes aiming to achieve a discriminatory optical force for chiral molecules.
The generation of light endowed with orbital angular momentum, frequently termed optical vortex light, is commonly achieved by passing a conventional beam through suitably constructed optical elements. This Letter shows that the necessary phase structure for vortex propagation can be directly produced through the creation of twisted light from the vacuum. The mechanism is based on optical emission from a family of chromophore nano-arrays that satisfy specific geometric and symmetry constraints. Each such array can support pairs of electronically delocalized doubly degenerate excitons whose azimuthal phase progression is responsible for the helical wave-front of the emitted radiation. The exciton symmetry dictates the maximum magnitude of topological charge; detailed analysis secures the conditions necessary to deliver optical vortices of arbitrary topological charge.
The development of viable all-optical data processing systems has immense importance for both the computing and telecommunication industries, but device realization remains elusive. In this Letter, we propose an innovative mechanism deployed as a basis for all optical transistor action. In detail, it is determined that an optically pumped system, operating just below laser threshold, can exhibit a greatly enhanced output on application of an off-resonant beam of sufficient intensity. The electrodynamics of the underlying, nonlinear optical mechanism is analyzed, model calculations are performed, and the results are illustrated graphically.