Enhancing light propagation for novel optical devices
Nano-optics has to do with the study of the properties and behaviour of light on scales much smaller than the wavelength of light. A subfield of nano-optics rapidly gaining interest is the study of surface plasmons (SPs). SPs are electromagnetic surface waves, or travelling waves of oscillating free electrons, those whose movement carries a charge or ‘conducts’ electricity in metals. The observation that the presence of SPs can enhance light transmission through thin metallic plates with arrays of tiny holes of diameter smaller than the wavelength of light, far exceeding what is predicted by mathematical theories, has suggested the possibility of nano-optics applications previously not exploitable. EU researchers working on the ‘Surface plasmon photonics’ (SPP) project set out to significantly enhance understanding and manipulation of SPs via nano-scale engineering. Advances in this area pave the way for a whole host of new photonic elements and devices based on photomaps (light emission images). Specifically, investigators focused on understanding the relationship (coupling) between light and SPs with the aim of controlling SP propagation and developing novel SP-based devices. SPP project members successfully developed a nanofabrication technique for producing thin metallic films with small arrays of holes used as gratings to couple light and SPs. In addition, they created a computer model of SP structures enabling computation of coupling efficiency. Project outcomes included a proof-of-concept SP circuit as well as production of patterned structures enhancing the transmission efficiency of light-emitting diodes (LEDs). Results of the SPP project demonstrated the viability of using SPs for photomaps as well as providing a computational model for calculating coupling efficiency between light and SPs critical to future design of photonic devices. Exploitation of results has the potential to place Europe in a leading position in the photomaps revolution enabled by increased understanding of SP properties and behaviour.
