All-Optical Near-Infrared Imaging via Semiconductor Nanocrystals

This project will develop new technology for Near Infrared (NIR) light imaging that is ultra-compact, transparent, and multi-colour. Human eyes only see 0.0035% (visible light) of the electromagnetic spectrum around us. Among all invisible spectra, the NIR range is of particular interest because of its broad application, for example for medical diagnosis, food quality control, autonomous vehicles, and night-vision. In conventional NIR-imaging technology, the NIR light gets converted to electrons and the resultant image is projected onto a display, where electrons get converted to light again to be viewed by the eye. Therefore, the converted images are monochrome. Moreover, this display blocks the perception of visible light, therefore disrupting normal vision. Also, such cameras are either only operational in a short wavelength band (e.g. Ge or InGaAs, converting up to 1800nm) or require cooling (e.g. InAs or InSb detectors operating at -200 C). Moreover, NIR cameras must be bulky to accommodate all components for light/electron conversions.

The detectors used in today's technology mean that the aforementioned limitations cannot be avoided. This project will develop a new technology for NIR-imaging that is all-optical, i.e. no longer requires optical and electric signals to be converted to each other. This technology will employ engineered nanocrystals, embedded within a thin and transparent layer, that capture the infrared light and re-emit it in the visible range. This approach will offer new functionalities as a result of:
i. being ultra-compact;
ii. forming colour images from invisible objects;
iii. being transparent in both visible and NIR ranges;
iv. capturing the visual information in the range of 400-4000nm, that is 10 times wider than the visible spectrum.

Such a revolutionary technology will be provided as a transparent thin and flexible layer that can upgrade any glass surface e.g. goggles and windows, to an NIR-imaging device, enabling a view over both visible and infrared frequencies concurrently. Therefore, information that is currently invisible to the naked eye will become visible - the ripeness of fruits and species health. This technology will also enable us to see invisible objects in the dark. Imagine no light pollution and a massive reduction in greenhouse gases associated with a world where the lighting was not required to see at night.

To develop this technology, specific nanocrystals to convert the colour of the light from NIR to visible will be designed and engineered. These nanocrystals, which are often a few hundred times smaller than a human hair, are transparent, i.e. do not block normal vision. The technique to fabricate and verify high-quality nanocrystals on a transparent surface (e.g. glass) has recently been invented by the applicant. In order to enhance the capability of these nanocrystals for capturing ultra-weak NIR light, the NIR will be mixed with an extra laser beam (also invisible) to generate a visual intensity in the visible range. Alongside this, various engineered nanocrystals within the same array, which enable conversion of different NIR frequencies into different visible frequencies will be employed. This will allow the generation of colour images from NIR objects. Finally, the extra laser beam and the nanocrystals will be embedded within a transparent, thin and flexible polymer cast that can be accommodated on any non-flat surface (for example windshields and goggles) and enable vision over the NIR range, without using bulky cameras. Industrial prototyping will be done in collaboration with Flexotronix, and industrial performance evaluations and environmental tests will be done in collaboration with QinetiQ, and Horiba Mira, respectively.

This project develops engineered nanocrystals, thousands of times thinner than a human hair, which convert NIR (invisible) light to the visible, where visible and infrared frequencies can be viewed concurrently. This technology will be developed, tested and commercialised within the UK. Nottingham Trent University (NTU) has a well-established technology transfer team who will work closely with the applicant to identify and protect IP arising from the Fellowship and then seek opportunities to generate impact through commercialisation. The university employs a pragmatic and flexible approach to commercialisation and both commercial license and spin-out/joint venture options will be explored. The impacts generated will be:

1. SECURITY AND SAFETY
1.1. Current NIR Cameras, e.g. night-vision helmets, are opaque in the visible; therefore they can be used only in dark environments. Thus, in urban war-fields, soldiers cannot determine if they need an infrared goggle when they enter an unsafe indoor environment. This hinders the fast action of soldiers when it is crucial. The unique ability of the proposed technology is to view both visible and infrared lights, concurrently. It will strengthen the capabilities of the UK armed forces and enable them to provide a more effective defence. QinetiQ is the project collaborator to realise this impact (see PtI). This technology will put QinetiQ in a predominant position in the market. This will also enable QinetiQ to provide the UK army with this novel technology.

1.2. This technology will enable the upgrade of any glass surface to a NIR-imaging device; this will apply to products ranging from windshields to house windows. Imagine no light pollution and a massive reduction in greenhouse gases associated with a world where lighting was not required to see at night. Flexotronix is the project collaborator to realise this impact (see PtI). This technology will capitalise on Flexotronix's investment in facilities for producing flexible electronics and optoelectronics products.

1.3. This technology will significantly increase the safety level, particularly in areas with low-levels of urban and road illuminations. It is an ideal technology for the next generation of vehicles in the automotive industry, particularly for autonomous vehicles. This impact will be developed in collaboration with Horiba Mira (see PtI), and they will become the supplier of this technology to the automotive, aerospace and rail sectors. This will also bring enormous economic opportunities for the UK, with autonomous vehicles sales set to be worth up to £52 billion by 2035 (Transport Minister Jesse Norman, 30 July 2018). t will benefit the UK future of mobility (Grand Challenge).

2. HEALTH AND WELLBEING
2.1. NIR detection is of high interest for medical imaging, as infrared light can penetrate the skin and provide images of organs. Our technology will enable developing new diagnostic schemes that are not possible today. This impact will be integrated on cutting-edge nasoscopes of Phaos Technology (Project partner) (see PtI) and brings a unique opportunity for them to develop the first bio-NIR-imaging nanoscopes. This is relevant to the UK Grand Challenge "Ageing Society".

2.2. Light-weight night-vision goggles can improve the life quality of people who suffer from the genetic disease retinitis pigmentosa (night blindness). Currently, such patients are obliged to use bulky night-vision helmets to put on when going out at night.