COSMOS Technology Translation Proposal

Lead Research Organisation: University of Cambridge
Department Name: Engineering


The primary aim of the original COSMOS Basic Technology Grant was to develop a new generation of compact laser light sources that were either continuously tunable or consisted of multiple wavelengths, and were based on soft materials such a polymers and liquid crystals. The emergence of such a technology will provide a light source that combines key features that do not exist in any present-day laser device namely, compact size, high quality output and a wide range of colour tunability. These lasers consist of two essential features: a light harvester that can be either excited optically or electrically and acts as a gain medium, and a colour selective structure (such as a photonic bandgap) that provides optical feedback. The COSMOS project involved the chemistry, physics and engineering of both the materials and the devices used as these laser sources. Over its duration the project synthesised new materials for light generation as well as characterised different devices for both laser and light emitting diode (LED) structures in the context of applications such as flat panel and projection displays, telecommunications and biomedical systems.This translational grant is designed to expand some of the key results from COSMOS and develop them further both in terms of their chemical components, physical structure and their overall implementation into different applications. One such thread is the further development of multi wavelength sources for holographic projection. The use of holograms to generate 2D and 3D images is a recently developed disruptive technology, with many advantages but with a major drawback of having to use 3 laser light sources to provide the 3 colour components in the image. The use of lasers sources improves the colour quality immensely but current semiconductor lasers are limited, expensive and difficult to mass produce. The lasers developed on COSMOS are ideal for this application as they can produce 3 simultaneous laser colours from the same single device cheaply, efficiently and also in a way that could well provide a solution to a further problem with these projectors; the image degradation due to laser induced speckle.The progress made by COSMOS into the materials suitable for infra-red (IR) lasing devices is also another area being expanded upon by this proposal. The ability to produce cheap tuneable IR sources is of great interest to many different biomedical applications as both human blood and tissue have unique signatory responses to different colours of light in the IR spectrum. One such biomedical system is optical coherence tomography (OCT) which allows a tissue sample to be imaged not only in cross section but also in depth (ie through the different layers of the sample). This is a very powerful tool in many medical areas such as retinal imaging where OCT can be used to diagnose pathologies such as diabetes and glaucoma. In the case of OCT, not only is the tuneable colour in the IR an important feature but also the coherence of the IR laser source is a vital parameter in the performance of the system. A key advantage of the soft materials used in the COSMOS laser sources is that the coherence properties can be optimised through both the choice of chemical components as well as the overall device structure. This adds another level of versatility into the already powerful diagnostics capabilities of an OCT system. Finally, the soft nature of these IR lasers also makes them an ideal candidate for embedding into polymer waveguide based systems such as those being developed for telecommunication network components. The ability to integrate the laser into the waveguides is an exciting new development which will be further explored by the translational grant proposed.

Planned Impact

The true impact of this Translational Grant proposal builds upon that of the original COSMOS Basic Technology Grant (BTG) through its multidisciplinary nature. Both the original BTG and this proposal span the full supply chain from materials chemistry through device development and into bench prototype applications. This methodology has allowed us to develop custom liquid crystal and light-emitting polymer materials and dyes for lasing structures and then combine them into new devices, characterise the physical properties of both the material and the device and then test those devices in different applications. In many respects, this has been achievable by virtue of the effective discussions and interactions across multiple disciplines and has yielded tangential benefits such as defining new applications. Furthermore, through this approach, new technologies have been formed based upon novel uses and combinations of the materials base. Hence we can complete the supply chain loop at the academic level to ensure that we get a chance to iterate towards an optimal solution. This methodology has proven very successful on the COSMOS BTG which involved Chemistry, Physics and Engineering in a very complex series of optimisations for both polymer and LC based light source and lasing systems. The academic (both in terms of publications and patent filings) output of COSMOS has shown that this approach works extremely well. Examples being, the development of the novel COPLED structure which has the best performance seen in the world, the development of soft material-based lasing systems into infra-red wavelengths, tuneable photonic band gap structures and multi-wavelength lasers and 2D laser arrays. These technologies will be of significant benefit to end-users of medical diagnostic techniques such as Optical Coherence Tomography, non-invasive techniques for treating ischemia and blood clots, and retinal imaging. The infrared liquid crystal lasers enable a choice of wavelengths that best suits the treatment and, through the development of a controllable coherence source, will potentially improve the performance of OCT providing clearer images of tissues and subcutaneous structures. The development of the COPLED technology for colour tunability and white light emission leads to large-area lighting applications, which will be of considerable benefit to society as a whole given the ever increasing demands for higher efficiency and lower cost light sources so as to reduce carbon emissions. Globally, the need for higher bandwidth communications is perpetual and thus complete all-optical matrix switching in complex waveguide geometries will have a profound impact on the telecommunications industry. All of these aspects are covered by the core technologies that have emerged from the COSMOS BTG and form the basis of the next phase of 'Translation' as described in this proposal. To ensure that the end-users that have been identified benefit from this research there will be a concerted effort to maintain constant two-way communications with UK and International Industrial Partners related to each element of the research so as to keep abreast with the requirements expected from the end-users.