The light wavelength is of the order of 1 micrometre. Optical components, from the pixels in displays and camera sensors to laser diodes and optical fibers, are Usually larger in size. Compared to the microelectronic chip with nanoscale transistor, photonics components are thus very voluminous.

This is especially a problem for integrated photonics "optic circuits IC" [1] which different functions (light sources, wavelength selective elements, sensors et c) integrated on one chip, and where large" footprint "as it is usually called a disadvantage in several respects: Difficult manufacturing complex integrated structures, higher energy, more difficult to make sensitive multichannel sensors, higher costs, greater material consumption.

New opportunities

In recent years, a branch of photonics, nanophotonics, has developed, where photonic elements substantially smaller than the wavelength of light developed. This has brought new opportunities and applications in the "Information & amp; Communnications Technology, "ICT and sensors, and the challenges of shrinking dimensions more for better performance. Nanofotoniken dominated hitherto largely of noble metals: gold and silver.

Are generally necessary, for this variant of the so-called plasmonic nanophotonics, a negative dielectric constant (relative permittivity) at that wavelength. The theoretical possibility to create plasmonic photonic nanostructures has been known for a long time, first through nanotechnology development, experimental breakthrough occurred.

In combination with silicon photonics [2] This research recent years rapidly increased in scope with applications in a variety of fields, from ICT to biosensors. And it is perhaps in the latter area that the most interesting progress can be made. And in both cases are integrated photonic circuits (F & amp; F), photonics correspondence with electronics integrated circuits (though with different functionalities) essential.

One example of a new type of nanophotonics-based biosensor is recently published in the scientific magazine "Photonics", a so called ring resonator plasmonisk [3] , see Figure, which with very high sensitivity, provided by light concentration in the" nano-gaps "between the gold structures and silicon ring, detects and identifies e.g. molecules in vitro in different fluids flowing in the" gaps ".

Another application of nanophotonics concerns the data center We use on a daily basis: In These, increasingly large, exponentially Increasing Electrical Power ice Consumed (eg in Facebook's plant in Lulea), a large part of Which is heat into electric transmission lines . Optical interconnection technology, "Optical Interconnect, OI" in the form of optical waveguides, can solve bothering the capacity (bandwidth) and the power problems and can be used between circuit boards, one circuit boards and Eventually one These circuit boards' chip.

Less is required here (nanophotonics), more power efficient and cheaper photonic components for transmitters, receivers and intermediate networks.OI is a prerequisite for the Continued Development of datacenters, Which means Greater volumes and pressure on costs for These photonic components and systems.

Material technology's relevance

But further development of nanophotonics will require advances in materials technology: Metals and other materials used have excessive energy losses for many applications: The more "nano" the faster subdued light out, and this complicates many applications, particularly in ICT. With better (lower loss) materials, substantially smaller structures can be produced, as a recent study published of a ring resonator with radii down to 50 nm, thus much smaller than the wavelength, showing [4] .

And we are still waiting for, and Trying to Achieve, the big breakthrough, a photonic integrated circuit comparable to CMOS technology in "footprint" and power consumption (but not in functionality).

An opportunity That is Currently being researched at KTH (Department of Theoretical Chemistry and Division of Photonics and Microwave Engineering) are Artificial atoms linked , so-called quantum dots. Here you will come close to Achieving this "CMOS goal".