Nanophotonics assisted advanced functional detectors and imagers

Russell Berrie Nanotechnology Institute – TECHNION

The FTA program at Technion deals with nanophotonic technologies for detection and sensing. These technologies are meant to support and advance the Israeli industry which specializes in light detection and imaging systems, distributed and dispersible sensors, medical imaging, high-resolution inspection, optical communications and of course defense oriented systems. Many relevant detector technologies have matured offering high level performances which are nevertheless insufficient and call for the development, in academia, of disruptive technologies.

The Technion FTA project seeks such breakthroughs through the development of new detection devices designed for the ultra violet (UV) to short-wave-infrared (SWIR) spectral ranges, all of which include some form of nano photonic performance enhancement. Some of these devices will comprise imaging systems to which elements of super resolution will be incorporated.

The main technology concepts concentrate on potentially cheap yet high performance device integrated with silicon. Additionally, cheap materials for special applications – e.g. flexible substrates are also included. The integration with silicon necessitates the incorporation of nanotechnologies. A second key concept is miniaturization. The small volume detectors ensure noise reduction and better carrier extraction and are imperative for intra-body implants, dispersible sensors etc. Finally, the demand for high level detector functionalities such as super resolution, hyperspectral, tunable, polarization state detection, etc. can be achieved by embedding nanophotonics in schemes which are highly viable to current manufacturing procedures.

The most pronounced single nano technology that is embedded in most proposed solutions is based on nanostructured metalo-dielectric composites. We are taking advantage of the booming technology related to metal optics, plasmonics and metamaterials and where Technion has several world leaders. Furthermore, the nanometal is employed not only for enhancing interaction of the light with the structure, but also as part of the electronic scheme.

Specific detection technologies include silicon over insulator (SOI) devices based on metal-insulator-semiconductor (MIS) structures with high-k dielectrics and metal nano particles, GaN compound semiconductor based detectors on silicon, nanowire-based detectors grown over silicon and organic semiconductor detectors on CMOS chips. The nanophotonic technologies that will be employed are: plasmonic nanoantenna, metal nanoparticles for spectral modification and enhanced sensitivity as well as latching, metasurfaces for focusing and polarization imaging, plasmonic hyperspectral filters, nanophotonic tunable filters, quantum imaging techniques.

The detection technologies to be developed will be integrated into demonstrators of functional imaging systems. Plasmonic based hyperspectral filters will be fabricated over specific detectors including organic imagers and SOI based broad-band detectors. Plasmonic antenna for light collection and enhanced absorption in thin layer detectors such as organic based imager, SOI detector and GaN quantum cascade detectors over silicon. Polarization detection pixels on SWIR detector. Plasmonic structures embedded on a visible – SWIR detector for super resolution imagers systems. To some of these schemes, we will apply compressive sensing methodologies in the imaging mode of operation.

Selected schemes developed in the integration phase will be further optimized as a demonstrator. It will involve integration of a detector arrays such as SOI based broad-band UV –VIS with plasmonic antennas, metasurface filters and emulated super-resolution imaging. Additionally, GaN on silicon SWIR detector arrays with plasmonic antennas for absorption efficiency enhancement and emulated super-resolution imaging. Finally, organic CMOS imager elements, with metallic nanoparticles, plasmonic spectral filters and metasurface focusing elements.