Ultra-Stable High-Performance Nanolasers

2015 was designated by the United Nations as the 'International Year of Light and Light-Based Technologies'. World-wide activities during the year highlighted the importance of photonics in industry, health care and education. Those activities - strongly supported by the UK - has led strong credence to the claim that photonics is the key technology of the 21st century. During the 20th century the UK delivered key advances in photonics technology including the development of low-loss optical fibres, pioneering work in semiconductor laser development and the invention of optical fibre amplifiers. That inventiveness is the foundation of optical fibre communications whose maturity has enabled year-on-year growth in data traffic including web-based products and services. The internet already consumes in excess of 5% of the world's electricity and is projected to consume 10% of that capacity very soon. As it is expected that growth in internet traffic will continue it is apparent that the demands placed on electricity sources could become unsustainable. Moreover, due to delays in decisions on the provision of new electricity generation capacity as well as vacillations in policy in respect of renewable energy sources, the UK is particularly vulnerable to excessive demands on electricity: the safety margin for generation has in the past few years declined from 15% in 2011/12 to a predicted 5% in 2015/16. The UK therefore has a particular need to advance technologies which will relieve demands on electricity usage. Photonics is such a technology and, specifically, the adoption of optical switching within compact photonic integrated circuits (PICs) will effect a dramatic reduction in electricity consumption: 40% of the internet electricity consumption is due to core switching operations.
One of the key requirements to achieving PICs is to miniaturize photonic components down to the nanometer scale, for instance, nanolasers. In this case, the bottleneck that must be overcome is due to the diffraction limit of light, namely, ~l/2n limiting the minimal dimensions of a laser cavity, where l and n are the free space wavelength and refractive index, respectively. It is also crucial to minimise energy consumption while using optical sources such as lasers for such compact PICs, and thus a laser with a very low threshold is essential. The use of surface plasmon polarition (SPP) modes excited at the metal dielectric interface offers a means for device size reduction down to the sub-wavelength range. The project will combine the expertise in simulation, design and testing of advanced nanolasers at Bangor, and the established epitaxial growth and advanced nanofabrication of GaN based optoelectronics at Sheffield to develop the first GaN based electrically-pumped single nanolasers. Building on analysis of stand-alone single nanolasers, it will be demonstrated that optimized nanolasers can be configured such that they remain immune to instabilities when subject to external optical influences. Such stability makes nanolasers ideal candidates for incorporation in complex photonic integrated circuits. This project will contribute to developing future photonic technologies which underpins the operation of the internet, Smart Phone and Tablet usage, satellite communications/GPS, Direct Broadcast TV, energy efficient solid state lighting, efficient solar power generation, consumer electronics, high capacity communications networks and data storage, advanced healthcare and ground-breaking biotechnology.

It is estimated that the global market for compound semiconductors is currently worth around $33.7Bn, with a compound annual growth rate (CAGR) of 17.3%. Expanding the UK commercial activity in compound semiconductors will be an important boost to the future development of the UK's economy. Therefore, the development of compound semiconductor based optoelectronics has the potential to benefit society by contributing to wealth creation and economic prosperity through the exploitation of scientific knowledge and promotion of economic and environmental sustainability.
The proposed project will impact the UK compound semiconductor industry, such as the Compound Semiconductor Centre (CSC) (project partner), and the nascent Compound Semiconductor Catapult, both located in south Wales, targeting to provide Europe's first prototyping facility dedicated to allowing businesses and academics to demonstrate new technologies based on Compound Semiconductor materials. The other semiconductor companies include Enfis (Swansea), Forge Europa Ltd (Cumbria), Zeta-control (Oxford), Orsam (Germany), OptoGaN (Russian), Philip-Lumileds (USA) etc. The proposed work will also impact a wider range of semiconductor process equipment manufacturers, such as device fabrication manufacturers (Oxford instrument) and MOVPE machine manufacturers (Aixtron in Cambridge/Aachen). Contact, communication and engagement with these industries will occur via the exploitation and development of existing personal networks, for example, a regular communication established with Aixtron through the very recent purchase of a new MOVPE machine which will be dedicated to the project, along with an agreement for supporting the promotion of Aixtron's products.
Any technological breakthrough made through the project will impact a wide range of academic areas in the field of III-nitrides and other III-Vs, such as a number of currently on-going projects at Glasgow, UCL, Cardiff, Oxford, Cambridge, Bath, Bristol. Advances achieved through this project will provide new collaborative opportunities including bids for further funding. Academic impact will also be realised through the UK Nitride Consortium (UKNC), which has 150+ members from industry and academy where the Sheffield team is an active member. Sheffield is host to the EPSRC National Centre for III-V Technologies (NC) which has a remit to supply device quality material to the UK Scientific Community and develop new technologies. The impact of the project on the whole UK semiconductor community will be further enhanced through the NC. The training provided for the junior researchers involved will also have a direct economic impact via the provision of skilled workers who may subsequently be employed by relevant companies, such as the large UK companies listed above, or create their own business in the field of photonics. The project will contribute to the pool of staff trained in leading III-nitride based device fabrication/design/characterisation, critical requirements in maintaining the competitive edge of UK companies.
The project will also seek to create awareness amongst government agencies and the wider public about the capabilities of photonics in general and nano-lasers in particular. This wider impact will particularly be promoted via the Photonics Academy of Wales @ Bangor (PAWB- Welsh for 'everybody') which, since 2011, has delivered hands-on photonics activities to well over 1000 participants in the 8 to 80 age range - including providing work-based learning to the photonics industry. PAWB, which is chaired by Shore and directed by Ray Davies, will organize an annual 'open day 'at its laboratory at which the objectives and achievements of the project will be communicated to a wide audience. The project also has a strong emphasis on the education of future scientists and entrepreneurs.