Periodic Report Summary 1 - APEX-SPP (Active and Passive Exploitation of Light at the Nanometre Scale)
Project Context and Objectives:
Light and the various ways it interacts with matter is our primary means of sensing the world around us. It is therefore no surprise that many technologies are based on light; for example submarine optical fibres make up the backbone of the Internet and display technology now delivers affordable and compact crystal clear televisions. However, light itself has a limitation that we are still trying to overcome: light cannot be imaged or focused below half its wavelength, known as the “diffraction limit”. To see smaller objects we have typically been constrained to using shorter wavelengths. Today, we are learning to overcome this limit by incorporating metals in optical devices. The proposed research investigates the use of metals to shatter the diffraction limit for creating new technological products, expand the capabilities of computers and the internet and deliver new sensor technologies for healthcare, defense and security.
With any new type of control come caveats. Firstly, it is difficult to focus light from its normal size beyond the diffraction limit. Secondly, having overcome the first challenge, light on metal surfaces is short lived due to a metal’s resistance. My research is geared to directly address these challenges. The core objectives of this research are: i) to develop a “Silicon plasmonics” technology to seamlessly transform optical energy between conventional and nano-scale optics in order to access strong linear and non-linear effects within compact optical devices; and ii) to develop commercially relevant “nano-laser” light sources for sensing applications and to explore the physics of light matter interaction at the nanoscale.
The first objective builds on Silicon Photonics, a well-established commercial optical communications architecture. This ensures that success of the project has the potential for short to medium term impact on photonics technology. At the half way mark, this research has progressed to the proof of principle stage with both theoretical and experimental works showing tantalizing results. In particular, a key geometry has been identified that will be most effective in delivering the “promise of plasmonics” within a Silicon architecture.
The second objective builds on recent breakthroughs on surface plasmon lasers, which can generate light directly on the nano-scale and sustain it indefinitely by laser action. This overcomes both challenges in nano-optics simultaneously. While conventional lasers transmit light over large distances, it is the light inside surface plasmon lasers that is unique and can be used for spectroscopy at single molecule sensitivities. To date the project has produced new plasmonic laser devices. Using these, the project has also been able to identify that they are ultrafast laser by examining their time dynamics. Moreover, this research aims to make this technology commercially relevant by using III-V semiconductor materials. The project has recently seen theoretical feasibility studies and experimental advances that suggest these devices are achievable in the near future.
Dr. Oulton’s research is also supported by an UK EPSRC research Fellowship and Leverhulme Lectureship at Imperial College London. The Marie Curie IRG supports Dr. Oulton’s reintegration in the European research community, most notable allow for collaborations with researchers within European institutions.