Hybrid Polaritonics

Lead Research Organisation: University of Southampton
Department Name: School of Physics and Astronomy

Abstract

Hybrid polaritonics combines the properties of different light emitting materials - organic polymers and semiconductors - in order to produce quasiparticles that combine the possibilities of both systems. "Polaritons" are quasi-particles that arise from strong coupling between light and matter. This means that they have hybrid properties, combining the mobility and flexibility of light, with the possibilities of interactions due to the matter component. At high enough densities, or low enough temperatures, polaritons can form a macroscopic coherent quantum state, a polariton condensate, or a polariton laser. Such a coherent state shows much of the same physics as Bose Einstein Condensation, as has been seen for cold atoms, but without requiring the ultra-low tempeatures required for atoms.

Hybid polaritonics focuses on how, by combining different "matter" parts of the polariton, one can push these temperatures even higher, up to room temperature, and how one can engineer completely tunable system. The matter part of a polariton can come from any material which will absorb and emit light at a specific wavelength. Much existing work on polaritons is based on the material being inorganic semiconductors. These can be grown controllably, and one can drive such devices by passing an electrical current through them to make a polariton laser. However, the coupling between matter and light in semiconductors is not strong enough for these devices to work at room temperature. In contrast, organic molecules and polymers can show huge coupling strengths, but are generally poor electrical conductors. Our programme is to combine the benefits of both systems to provide a whole set of devices, operating at room temperature, based on the formation of polaritons. These devices will range from polariton lasers (providing a route to easily tunable lasers with very low threshold currents), to Terrahertz light sources (with applications in non-invasive medical imaging and explosives detection), to ultra-efficient light emitting diodes.
To reach these ambitious objectives, we need to combine expertise from a wide number of fields. Our team contains world experts in light emitting polymers, semiconductor growth, characterisation and spectroscopy of polaritons, and in theoretical modelling. Members of our team have previously achieved the first realisations of polariton lasing, of strong coupling with organic materials, and of building hybrid polariton lasers. The possibility to combine this expertise draws on the unique strengths that the UK currently has in this area, and enables the combination of this expertise to be focussed on providing room temperature devices based on hybrid polaritonics, and to revolutionise this field.

Planned Impact

The economic impact of investment in fundamental science based around photonic /
optoelectronic technologies is significant. The European Commission Photonics 21
industry group has stated "Photonics technologies underpin at least 10% of the
European economy, and that reliance will increase as those technologies are further
developed in the next decade." The growing importance of photonics is also recognized
by the EU Photonics Unit, who predict that photonic technologies will have a growth
rate > 8% and will reach a global market of Eur 600 Bn by 2020. Indeed, there are
around 500 companies in Europe that currently develop photonic technologies and
employ 300,000 people (mostly in SMEs). Major growth is expected in the coming years,
however it is clear that developments over time scales of 15+ years will only come
through continued state-sponsored basic research in projects such as that proposed
here.
Our Programme Grant is designed to address the development of new physics that will
feed into advanced optoelectronic devices. Polaritonic technologies - devices based on
polariton physics - are set to bring the exotic world of quantum coherent phenomena
into everyday life. The physics that we will develop will directly underpin the
development of technologies that rely on the quantum-mechanical properties of excitonpolaritons.
Such technologies are anticipated to have significant social and commercial
value, as they will directly address a number of areas including medicine, environmental
protection, security, data-communication, and computing.
The polariton devices that will be designed and studied will include polariton logic gates
and optical integrated circuits, polariton sources of non-classical light and entangled
photon pairs and polariton-based quantum annealing processors. The realisation of
these devices would be a giant step forward in development of quantum technologies, in
particular, quantum simulators. This project thus directly addresses one of the Grand
Challenges in Physical Sciences formulated by the EPSRC: Quantum Physics for New
Quantum Technologies. The direct beneficiaries of our work include the banking sector,
security and communication industries.
Further applications of our research are anticipated in low-cost, portable and coherent
terahertz radiation sources. Such technologies are anticipated to have a range of
applications from the non-invasive detection of cancers in the human body to the
detection of the chemical signatures of explosives. We will also explore speculative ideas
to use polariton physics to improve the emission efficiency of organic light-emitting
diodes. Here, our goal is to bypass the (normally non-emissive) triplet states formed in
an OLED device and rapidly transfer them to emissive polariton states. If successful, this
concept could present a significant opportunity to OLED display manufacturers, as this
would allow triplet states to be harvested without the necessity to use expensive
platinum or iridium metal complexes in display technology. Progress in this area could
produce valuable intellectual property that could be exploited in the highly lucrative
OLED display market that is expected to reach $25.9bn by 2018 (Transparency Market
Research).
This project will also have direct impact through the training given to a number of
PDRAs and postgraduate students (from relevant CDTs or DTGs) who will be closely
involved with the research. This training - in both experimental and theoretical
methods - will help provide a cohort of highly skilled researchers who are prepared for
careers in both academic and industrially based research in the areas of photonics and
optoelectronics.

Publications

10 25 50
publication icon
Askitopoulos A (2018) All-optical quantum fluid spin beam splitter in Physical Review B

publication icon
Askitopoulos A (2016) Nonresonant optical control of a spinor polariton condensate in Physical Review B

publication icon
Bhattacharya A (2017) Room-Temperature Spin Polariton Diode Laser. in Physical review letters

publication icon
Cammack H (2018) Coherence protection in coupled quantum systems in Physical Review A

publication icon
Cilibrizzi P (2016) Half-skyrmion spin textures in polariton microcavities in Physical Review B

publication icon
Cilibrizzi P (2015) Polariton spin whirls in Physical Review B

 
Description We aim to deliver the first electrically pumped room temperature polariton laser. Our strategy is to develop a hybrid organic/inorganic strongly coupled microcavity that utilizes the inorganic epitaxy for electrical injection and the organic component to retain strong coupling at room temperature. We have experimentally realised a polariton quantum simulator based on a lattice of coupled polariton condensates. We have also designed an ultrafast optical switch based on exciton-polaritons. In organic microcavities, we have realised an orange laser. We have also found a dramatic variation of the injection current in hybrid organic-inorganic microcavities. We have demostrated the polariton lasing in a hybrid GaAs/MoSe2 microcavity that is the first evidence of Bose-Einstein condensation in an atomically thin crystal film.
Exploitation Route Through the industrial engagement by IBM (Zurich), CDT (Cambridge) and other groups. The development of our research through the network of national and international collaborations is envisaged.
Sectors Digital/Communication/Information Technologies (including Software),Electronics

URL https://sites.google.com/site/hybridpolaritonicspg/
 
Description Our project involves active engagement from our partners, IBM Research, Cambridge Display Technologies, Nanoquanta, and KP Technology. Discussions with these partners has shaped our research plans, and we will ensure our research plan remains aligned with their priorities by including representatives of these companies on our advisory board, as well as ensuring there is representation of our partners across the range of workshops and meetings we will hold to discuss our progress and plan our future program. In addition to these mechanisms to ensure strategic focus, we will encourage graduate students working within the remit of our program to be seconded to our industrial partners, either to work on projects directly related to their ongoing research, or to intermit their PhD in order to carry out internships with these industrial partners. For example, KP Technology and St Andrews have experience of running joint internship projects for St Andrews students, and these would be available to PhD students aligned to the programme. We have also started a joint PDRA program with the university of Wuerzburg. The PDRA employed by Soton is spending 9 months per year in Wuerzburg working on the MBE growth of structures that are subsequently studies in Southampton and Sheffield.
First Year Of Impact 2017
Sector Digital/Communication/Information Technologies (including Software)
Impact Types Economic

 
Description Laidlaw Internship: Ryan Moodie
Amount £4,110 (GBP)
Organisation University of St Andrews 
Sector Academic/University
Country United Kingdom
Start 06/2016 
End 08/2016
 
Description Royal Society International Exchange: Prof. Allan Macdonald
Amount £9,800 (GBP)
Funding ID IES\R2\170213 
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 01/2018 
End 12/2019
 
Description Physics Today 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Recently published general article on "The new era of polariton condensates" in the American Physical Society magazine "Physics Today". The magazine has a circulation of over 100,000.
Year(s) Of Engagement Activity 2017
URL http://physicstoday.scitation.org/doi/10.1063/PT.3.3729
 
Description Science Discovery Day 2017 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact "Synchronised swinging": an interactive activity on coupled oscillators and pendulum, as part of our annual Science Discovery Day, which is targetted at families via advertising through schools and third sector groups (youth clubs, Scout and Guide movements). The attendance at the event was over 600 people over the course of 6 hours.
Year(s) Of Engagement Activity 2017