The past decades have seen a development in integration density of photonic integrated circuits that outpaces Moore´s law. A continued progress into the truly nanodevice realm has to rely on a combination of structural and material development. Nanophotonics is a technology where the flow of optical-frequency electromagnetic radiation is engineered in dimensions, or with function-enabling feature-sizes, smaller than the vacuum wavelength. Research on nanophotonic devices will thus be essential to achieve the above-mentioned high photonic integration density.
Research topics for nanophotonic devices in our Linné center include e.g. subwavelength structures and devices, metamaterial-based nanophotonic devices, and device nanofabrication technology and characterization.
Guiding of light at a subwavelength scale is essential in order to be able to obtain a high photonic integration density. Our ways of achieving subwavelength devices include using plasmonic (metallic) structures, quantum dots, and hybridize Si nanostructures with III-V based quantum dots or other optically active and tunable materials.
Using optical metamaterials (such as photonic crystals and negative index materials), our main goal is to design novel types of nanophotonic devices with special functionalities which cannot be obtained using normal materials. Using photonic crystals, one can e.g. obtain high quality-factor resonators, ultra-compact optical filters, high-speed switches, bio-sensors, delay-lines based on the slow light phenomena, etc. As for negative-index materials, we will design and fabricate novel devices such as lenses with subwavelength resolutions, open cavities, and even invisibility cloaks (like the one Harry Potter has).
Nanophotonics and nano optical devices rely largely on advanced fabrication and characterization tools. To be competitive, these tools need to be further developed and improved. On the fabrication side, this includes electron-beam lithography, nanoimprint lithography, focused ion-beam machining, and other nano-fabrication techniques with goals set for increased manufacturing precision, down to the few nm range. On the characterization side, relevant techniques that will be employed include high-resolution microscopy (e.g. scanning near-field optical microscopy), efficient optical characterization set-ups, femto-second pump-probe facility, etc.