29 June 2012A collaboration between Electrical and Electronic Engineering, Chemistry and Physics as part of the Bristol Centre for Functional Nanomaterials (BCFN) has resulted in a highly prestigious Post Deadline paper at the European Conference on Integrated Optics in Barcelona, Spain in April 2012. This work was carried with supervisors Dr Martin Cryan from Electrical and Electronic Engineering and Prof Andrew Orr-Ewing from Chemistry as part of an Extended Project by Philip Bassindale and Jack Munns, two first year PhD students in the BCFN Doctoral Training Centre based in the Nanoscience and Quantum Information building. Dr Cryan, a member of the Photonics Research group, has been developing modelling and fabrication techniques for nanoantennas over the past two years and his PhD student Jamie Stokes designed the nanoantennas used in this work.
Nanoantennas, like their more conventional Radio Frequency counterparts, can radically effect the emission or absorption of light, however they are around a million times smaller being 100’s of nanometres in scale. Only in recent years have nanofabrication techniques such as Focused Ion Beam etching become available to fabricate these wavelength scale devices. Almost any application involving light can benefit from using nanoantennas, this work shows how they can be used to enhance the light emission from fluorescent molecules which are used throughout biology and chemistry for imaging structures and tagging and tracking cells and molecules. By enhancing light emission nanoantennas can dramatically increase the sensitivity of these techniques allowing very small analyte volumes to be used, a key requirement for lab-on-a-chip technologies. Other nanoantenna applications being studied by Dr Cryan are in solar cells and plasmonic flat lenses for lasers.
This was a truly interdisciplinary piece of work with designs done in Electrical Engineering, fabrication done by Dr Peter Heard in the Interface Analysis Centre, dye-doped polymer prepared in Chemistry and measurements performed in Phyics by Dr Andrei Sarua, part of Prof Martin Kuball’s Applied Spectroscopy group. The figure below shows the fabricated array of dipole antennas, this was then spin coated with dye-loaded polymer and measured using a scanning microphotoluminescnce system as shown below. The figure shows how much stronger light emission is observed from the array region as compared to the surrounding areas.
The team will now go on to show how different array geometries can be used to focus and steer light with one exciting prospect being the ability to electronically steer and shape the light beam just like Radio Frequency phased array antennas have been doing for more than half a century.
 J.Stokes, P.Bassindale, J.W.Munns, Y. Yu, Z.H.Yuan, G.S.Hilton, J.R.Pugh, A.Yang, A.Collins, P.J.Heard, R.Oulton, A. Sarua, M.Kuball, A.J.Orr-Ewing and M.J. Cryan “Direct Measurement of the Radiation Pattern of a Nanoantenna Dipole Array”, European Conference on Integrated Optics ECIO2012, Sitges, Barcelona, Spain April 2012, Post Deadline Paper