NANOSCOPE: looking inside a living cell with nanoscale resolution

The increase in resolution of observational instruments is one of the main drivers of science and technology. Optical, electron and scanning microscopy have facilitated an uncountable number of key discoveries in biology, medicine, geology, chemistry, materials research and physics, while these instruments are now routinely used in hospitals, research and industrial laboratories. Although the wide application of lasers has led to the development of a number of high-resolution nonlinear optical techniques, these techniques only work with narrow classes of specimens and require the application of high and often destructive light intensity levels. Electron microscopy can provide high resolution, but living cells cannot survive the required vacuum, exposure to intense electron beams or sometimes necessary sample metallization. High resolution tunnelling and optical scanning microscopes (SNOM) are not capable of seeing internal sections of a living object - or indeed any object - without destroying it: their operation depends on the presence of probes a few nanometres from the feature being imaged. Therefore, it has not been possible so far to look inside a living cell or small biological object non-destructively with sub-wavelength resolution using low intensity light and without dependence on specific molecular absorption resonances.In the last few years we have witnessed the remarkable development of a new concept of optical super-resolution, proposed by Profs. Sir John Pendry and Victor Veselago. It is based on a negative-index material that refracts light in the opposite direction to normal media. Although the technology has been proved in principle, the development of a suitable optical negative index material for the negative index super-lens will require many years of work to overcome limitations of the nano-fabrication process and losses. Here we propose to develop a technology ALTERNATIVE to the Pendry-Veselago super-lens that will make possible sub-wavelength imaging. Our concept centres around a remarkable theoretical discovery published in 2006: Profs. Sir Michael Berry and Sandu Popescu (Bristol University and HP Laboratories) predicted that a properly designed grating structure could create sub-wavelength localisations of light that propagate several wavelengths away from the structure, into the far-field. They relate this effect to the fact that band-limited functions are able to oscillate arbitrarily faster than the highest Fourier components they contain, a phenomenon known as super-oscillation. This gives an opportunity of colossal importance: in principle it is possible to create an optical instrument with resolution far exceeding the wavelength limit and operating with specimens located a few tens of microns away from the lens without developing negative index materials. Recently our group demonstrated a far-field subwavelength concentrator of light, a nanolens which is an appropriately designed array of nano-holes that creates optical super-oscillations and focuses coherent radiation into a sub-Rayleigh resolution spot. This provides the foundation for our proposal that will give the UK science an exceptional opportunity to develop a new technology which was born in this country. The main goal of the proposed research is to develop a new generation of non-invasive super-resolution optical technologies (nanoscope) based on the development of the super-oscillation concept and to demonstrate the use of nanoscope instruments with the hope of imaging the inside of a living cell and perhaps a single large bio-molecule. The technique will also provide new opportunities for trapping and manipulating extremely small objects, for instance inside a living cell or detecting the motion of nanoparticles on optical landscapes. Beyond the biological applications this project will have a colossal impact on all types of imaging application and on lithography high-density component integration.