All-Silicon On-Chip Optical Nanoantennas as Efficient Interfaces for Plasmonic Devices

Plasmonic technology promises to unfold new advanced on-chip functionalities with direct applications in photovoltaics, light-matter interaction, and the miniaturization of optical interconnects at the nanoscale. In this scenario, it is crucial to efficiently drive light to/from plasmonic devices. However, typically used plasmonic wires introduce prohibitive losses, hampering their use for many applications. Recently, plasmonic nanoantennas have been proposed to overcome this drawback, not only providing a notable loss reduction, but also an enhanced on-chip flexibility and reconfigurability. Nevertheless, these devices still perform poorly for long-reach interconnects, owing to their low-directive radiation and low efficiency. Here, we introduce a class of slot-waveguide-based silicon nanoantennas that lift all these limitations and show their feasibility to be connected directly and efficiently to plasmonic devices. To test the performance of these antennae, an on-chip plasmonic-dielectric interconnect is experimentally demonstrated over distances as high as 100 mu m. In an outstanding manner, our wireless scheme clearly outperforms previous plasmonic approaches in terms of link efficiency and effective gain. This work paves the way for the development of ultrafast on-chip wireless reconfigurable and flexible interconnects and, additionally, opens new avenues in optical manipulation and sensing applications.