IMEC has developed a technique to integrate high-speed CMOS electronics and nanophotonic circuitry based on plasmonic effects. Metal-based nanophotonics (plasmonics) can squeeze light into nanoscale structures that are much smaller than conventional optic components. Plasmonic technology has the potential to be used in applications like nanoscale optical interconnects for high performance computer chips, extremely sensitive (bio)molecular sensors, and highly efficient thin-film solar cells.
Top left: Schematic overview of the device, showing focused illumination of a slit in the waveguide using polarized light. This results in plasmon excitation of the waveguide for the red polarization and the generation of electron/hole pairs in the semiconductor.
Bottom left: SEM picture of a typical device.
Top/bottom right: Photocurrent scans for the “red” (bottom) and “blue” (top) polarization indicate a strong polarization dependence of the photoresponse.
IMEC’s results are published in the May issue of Nature Photonics. Here’s the abstact of their article:
Plasmonic waveguides offer promise in providing a solution to the bandwidth limitations of classical electrical interconnections. Fast, low-loss and error-free signal transmission has been achieved in long-range surface plasmon polariton waveguides. Deep subwavelength plasmonic waveguides with short propagation lengths have also been demonstrated, showing the possibility of matching the sizes of optics and today’s electronic components. However, in order to combine surface plasmon waveguides with electronic circuits, new high-bandwidth electro-optical transducers need to be developed. Here, we experimentally demonstrate the electrical detection of surface plasmon polaritons in metallic slot waveguides. By means of an integrated metal-semiconductor-metal photodetector, highly confined surface plasmon polaritons in a metal-insulator-metal waveguide are detected and characterized. This approach of integrating electro-optical components in metallic waveguides could lead to the development of advanced active plasmonic devices and high-bandwidth on-chip plasmonic circuits.