Grant: Idea to Innovation

Digital colour imaging is a ubiquitous technological process that relies on the combination of responses from distinct red, green, and blue pixels to produce full colour images. This colour sensitivity is achieved by colour filters absorbing light of all colours other than the one being imaged by a given red, green, or blue pixel. This absorption however limits the efficiency of the sensor to less than 33%, just from the colour filter alone. Colour splitters aim to remove this source of loss. Instead of absorbing incoming light, the proper colour light is redirected into the corresponding pixel, thereby allowing a theoretical tripling of light collection efficiency. This project is specifically focused on the development of nanophotonic colour splitters that rely on an optimized geometric structure of a non-absorbing material to perform this colour sorting. This new type of colour splitter would provide a drop-in replacement for on the market colour filters, while greatly enhancing the efficiency of the system. Furthermore, additional colour channel information can be integrated into the design, allowing for multi-spectral imaging to be performed. The objectives of the purposed work are: (i) further computational optimisation of the design for three-colour and four-colour multi-spectral colour splitters for 2000 nm pixel CMOS sensor arrays, (ii) fabrication and testing of improved single-layer color splitter structures, (iii) fabrication and testing of multilayered splitter structures and (iv) develop a multi-spectral splitter to capture non-visible or extended colour space wavelengths. These techniques can have applications in remote sensing, medical diagnosis, material science and consumer electronics.