Engineering Quantum Technology Systems on a Silicon Platform

The vision of this project is to develop practical quantum technology for the accurate measurement of electrical currents and to develop high sensitivity detectors for gases such as carbon dioxide, methane (the gas used to heat homes) and carbon dioxide. Single electron transistors allow only one electron to travel through the device when switched on to form the electrical current. If the control gate is switched at a high frequency then the current through the device is simply the frequency times the charge on an electron and by counting the number of electrons, the current can be accurately measured. All such devices to date only work at low temperatures due to the small energy difference between the quantum states required for the transistor. I am proposing to make a single electron transistor which is far smaller than any previous reported device that will have large energies between the quantum states and operate at room temperature.

Gas molecules absorb light at very specific wavelengths which in the mid-infrared part of the electromagnetic spectrum correspond to vibrational energy of the bonds which hold the atoms together to form the gas molecule. This provides a molecular fingerprint as each molecule only absorbs specific wavelengths which can therefore be used to identify the gas. Gas detectors already exist for carbon dioxide, carbon monoxide and methane gas by measuring the absorption of light at the molecular fingerprint wavelength but the sensitivity for small battery powered detectors in the home is at the level of parts per million. For many scientific, healthcare, industrial and security applications sensitivities require to be at least a thousand times better. To date systems for measuring at this accuracy are large, bulky and require large lasers. This proposal will use quantum technology to build a far smaller and cheaper chip scale gas detector with parts per billion sensitivity that could be integrated into mobile phones or used for battery power sensors.

I am proposing to use the quantum nature of light to produce 2 individual packets of light called photons which will be at the same wavelength and at the same phase where the peaks and troughs of the waves are at the same points in space as the light travels through a waveguide. Heisenburg's uncertainty principle only allows us to measure the amplitude or the phase of the photons with a specific accuracy and the product is a constant. If we squeeze the phase of the light so that the accuracy in measuring the phase is reduced then we can measure the amplitude more accurately since it is only the product of the two that we cannot measure at a higher accuracy. This quantum approach of squeezing light allows far more sensitive measurements that are forbidden in classical measurement systems.

The project brings together a range of UK companies, government agencies, standards laboratories and universities to deliver the portable current standard and the high sensitivity gas detector. I will be supplying demonstrators to a range of collaborators who will evaluate the performance with successful devices being transferred to UK companies to help develop next generation products. The project will also train 2 research associates and 2 PhD students in quantum technology.

The quantum technologies being developed in this proposal will deliver both economic and social benefits in the areas of environmental monitoring, safety, standards, security and healthcare. The first beneficiaries are the UK companies who are partners to this proposal. They will gain new technologies and either new or improved products that can be taken to market for improve economic benefit.

The Ministry of Defence (MOD) has an annual procurement budget for technology of circa £18 Bn. DSTL has indicated an MOD requirement for the quantum technologies to be developed in this proposal which includes sub-shot noise portable chemical and biological weapons detectors and gravity imagers. I am engaged with Toshiba to investigate quantum communications systems which could potentially provide completely secure communications for internet commerce thereby reducing crime.

Market surveys undertaken by consultants for the Scottish Enterprise CENSIS project have indicated that the global market for gas detectors utilised for indoor air quality, safety, medical and industrial use was $1.9 bn in 2009, and is forecast to grow to $2.2 bn by 2015. The markets for mid infrared optical sensors are anticipated to reach $2.5 bn by 2015, growing in response to demand for remote devices that are network configurable and accessible. Further, the World Health Organisation estimates that more than two billion illnesses are caused by unsafe food every year, and in the developing world alone, each year 2 million children die from contaminated food and water. In the US, this claims an annual death toll of more than 3000 people, costing up to £35 bn in medical costs and lost productivity. Diarrheal illnesses are one of the leading causes of death worldwide.

Optical measurement techniques in the mid-infrared spectral range are highly specific to individual molecules, however the challenge today is that sources and detectors with the required specification are much too expensive for the realisation of practical sensing systems. This project could have a major impact both economically but also socially by producing far cheaper mid-infrared detector technologies on a cheap and easy to manufacture silicon platform that could address the above markets and applications. In doing so there is enormous potential to improve the quality of life across the world through better healthcare provision, better environmental monitoring and security detection of chemical and biological weapons.

The OECD Health Data show that an average of 8.9 % of GDP in developed countries is spent on healthcare costs. The NHS in the UK is already in severe financial problems due to an aging population and increases in healthcare costs as new treatments are implemented for previously incurable illnesses. This proposal is one of many aiming to produce point of care detectors and sensors which can be integrated into portable devices such a mobile phone which would enable personalized medicine with the potential for significant reductions in healthcare costs and improvement in quality of life. Early diagnosis and treatment is key for many diseases for good outcomes and also to reduce the time spent in hospitals. Breath analysis of ammonia is one technique for early state detection of certain tumours in oncology.

Such personalized healthcare detector solutions are urgently needed taking into account the UK and Europe's aging population, the even more demanding constraints on resources and patient empowerment. 2012 estimates on cost savings from m-Health for chronic diseases in OECD countries are valued at 227 - 273 billion Euros worldwide. M-Health was around a 2 billion Euro market in 2012 according to CSMG, and it is expected to grow over the next five years at a 25 percent CAGR.