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The Background

The physical laws of diffraction generally limit the spatial resolution of optical systems, being about 200 nm for light in the visible range. That is the reason why we usually cannot directly observe e.g. single proteins, DNA molecules or the development of internal cellular macromolecular complexes and structures with conventional optical microscopes. Attempts to overcome this limit have led to “super­-resolution” techniques, (like STED, STORM, PALM, NSOM, etc.) where all of them are based on bulky optical systems and complex sample preparations. The Chemistry Noble Prize 2014 awarded to the development of super-resolved fluorescence microscopy to overcome the limit of diffraction had proven the value of these techniques.

ChipScope – The Overall Goal

The overall goal of the project is to develop the scientific and technological basis for a completely new approach to optical super-resolution, based on semiconductor nano light emitting diode (nanoLED) arrays with individual pixel operation, which will lead to extreme miniaturisation and simplicity for performing super-resolution microscopy. In the long-term this will revolutionize optical microscopes with super-resolution capabilities, making them chip-sized, convenient, affordable, and ubiquitously available, not only for laboratories working in manifold research fields, but also in everyday life.

 ChipScope – The Core Idea

The core idea of the project is to use spatially resolved illumination instead of spatially resolved detection for achieving microscopy functionality with super-resolution.This will be made possible by developing chip-based nanoLED arrays with light emitting diode (LED) dimensions and distances much smaller than the wavelength of visible light.

ChipScope principle for achieving sub-wavelenght resolution (not to scale). An array of nano LEDs (pitch <50nm) is combined with a light integrating photodetector. The sample (e.g. a biological object like a cell) is placed on top of the nano LED array. The nano LEDs are switchend independently on and off, one after the other, in synchronization with a broad area, single pixel, photodetector.

Thus, ChipScope will develop the highest resolution LED arrays in the world. These new devices will enable novel science in general and super-resolution in particular. Specifically, LED arrays with LED dimensions below 50 nm will be targeted, where each nanoLED is directly addressable. Switching the LEDs in the array on and off, one by one, and at the same time detecting the light transmitted through the sample/object in direct contact with the nanoLED array will allow constructing a direct transmission image, with a resolution much higher than the diffraction limit.

Using high repetition rates, structured illumination and imaging can be explicitly fast, even in “real time”. Also, with modulation rates in the sub-nanosecond range, these ChipScopechip microscopes will also include spatially resolved fluorescence microscopy capabilities for imaging molecular events.

The project is based on highly competitive GaNnanoLED co-development in combination with CMOS photodetector integration with single photon capability. The project includes strong theoretical activities in order to explore the fundamental physics and potential limitations of the ChipScope approach by simulating real devices.