Nanophotonic Computing Based on Optical Near-Field Interactions between Quantum Dots

Abstract

SUMMARY We approach nanophotonic computing on the basis of op-tical near-field interactions between quantum dots. A table lookup, ormatrix-vector multiplication, architecture is proposed. As fundamentalfunctionality, a data summation mechanism and digital-to-analog conver-sion are experimentally demonstrated using CuCl quantum dots. Owing tothe diffraction-limit-free nature of nanophotonics, these architectures canachieve ultrahigh density integration compared to conventional bulky opti-cal systems, as well as low power dissipation. key words: nanophotonics, optical signal processing, optical near-field,information processing, nanophotonic computing 1. Introduction To accommodate the continuously growing amount of datatraffic in communication systems [1], optics is expected tofurther enhance the overall system performance by perform-ing certain functional behavior [2]. In this regard, so-calledall-optical packet switching has been thoroughly investi-gated. Also, the application of optical features, such as par-allelism, in computing systems has been investigated sincethe 1970s [3],[4]. However, many technological difficultiesremain to be overcome; one problem is the poor integrabilityof the hardware due to the diffraction limit of light, whichis much larger than the gate width in VLSI circuits. Thisresults in relatively bulky hardware configurations.Nanophotonics, on the other hand, is free from thediffraction limit since it is based on local electromagnetic in-teractions between a few nanometric particles, such as quan-tum dots (QDs), via optical near-fields [5]. From an archi-tectural perspective, this drastically changes the fundamen-tal design rules of optical functional systems.In this paper, we propose a nanophotonic comput-ing architecture composed of table-lookup operations, asschematically shown in Fig.1. A large amount of lookup-table (routing table) data can be recorded by configuring the