Photonic integration of 2D materials for room temperature single photon generation

Lead Research Organisation: University of Exeter
Department Name: Engineering

Abstract

Modern society is built upon our ability to communicate sensitive information securely, which is protected through cryptographic methods that rely on the inability of even the most powerful supercomputers to solve certain mathematical problems. However, with the advent of quantum computing it is only a matter of time before this security is breached. It is fortunate that quantum technology can also guarantee secure communication, where Quantum Key Distribution (QKD) employs the fragile nature of quantum states to detect any breach of security. QKD is a mature technology with commercial systems currently reaching the market for the most critical of applications, such as national security and high value financial transactions. With the ever-increasing reliance on mobile technology and the growing threat to conventional cryptography it is vital that solutions compatible with handheld devices are developed. This is currently limited by the availability of suitable single photon sources, which we aim to address in this project through the development of chip integrated quantum light sources built from two-dimensional (2D) materials.

So called 2D materials, those with a thickness of just a few atomic monolayers, have great potential in this area. The first to be discovered was graphene, an isolated single layer of carbon atoms, first produced in a laboratory in 2004. Remarkably, the first graphene samples were isolated using sticky tape to peel away atomic layers from graphite, which is not dissimilar to the "lead" found in ordinary pencils. As a result, graphene samples can be produced easily and cheaply, allowing scientists to make rapid progress in the understanding of physical processes and unlock the potential for applications. This success with graphene has inspired scientists to look for other atomically thin materials, with considerable success and an ever-expanding list of stable 2D crystals. Unlike graphene, several of these emit visible light making them great contenders for next-generation optoelectronic devices. Very recently, with the discovery of single photon emitters reported in monolayers of transition metal dichalcogenides and boron nitride, this potential has been expanded to quantum photonic applications. In particular, atomic-scale defects in boron nitride have been shown to emit single photons at room temperature, which puts 2D materials amongst a very small number of room temperature quantum emitters. Early experiments indicate that high brightness and stable emission could mean boron nitride is unmatched as a system for room temperature quantum photonics.

In this work we seek to take full advantage of this potential and will investigate the physical processes and atomic structure underpinning the quantum emission, methods of fabrication and photonic control of the emission. Ultimately, the aim will be to realise a platform consisting of defect emitters coupled to photonic circuits. Photonic integrated circuits enable the control and manipulation of light at the chip-scale and can benefit from the same economies of scale that have driven the microelectronics industry; namely that lithographic techniques can be employed to compress a large number of components into a very small volume to realise complex and efficient functionality. Development of integrated photonics is being driven by the huge power demands of data centres, which are increasingly using optical interconnects and the direct integration of photonics with CMOS electronics. Such photonic integrated circuits are important for the inclusion of quantum photonic devices within mobile devices because of the obvious size and weight constraints. The goal of this project will be to bring together quantum emitters in 2D materials with integrated photonics to provide a room temperature and portable solution for quantum secure communication.

Planned Impact

This project can make a significant contribution to the delivery of economic and social benefits. Society is increasingly dependent on communications infrastructure and mobile computing devices. As a result huge quantities of sensitive data, including financial and personal information, are communicated on a daily basis and it is imperative that this data is kept secure. Quantum technology provides the means to guarantee this security, and this project will make a direct contribution to enabling the protection of data transmitted by mobile devices. The importance of secure communication also assures the economic benefits of this research; Quantum technologies in general provide a huge opportunity for wealth generation, with excellent potential for high-value manufacturing and new spin-out companies. One example of the potential value of quantum secure communication for mobile technology is in secure ATM transactions, a market with a predicted worth of £100m per year. The development of chip integrated and efficient quantum light sources, is fundamental to such systems and this research has real potential to make a significant impact in this area. A strong interaction with the EPSRC Quantum Communications Hub and the University of Bristol will provide a great opportunity to promote our work to quantum technology communities in the UK and to explore industry partnerships. This link will also enable the assessment of our devices in a quantum key distribution test-bed and form a partnership for securing future resources.

To realise the bright future of quantum technology, for applications and wealth generation for the nation, also requires highly trained scientists and engineers. This project provides a superb opportunity for the early career researchers involved to experience a cross-disciplinary project, gain first-hand experience of quantum photonic engineering and interact with European and industrial collaborators. Quantum technologies provide a huge opportunity for UK science and technology and it is imperative that students receive training in this area. The scientific advances in semiconductor physics, quantum optics and integrated photonic devices that will arise from this project will provide a strong training opportunity for the junior researchers and students involved. The project will provide inspiration to undergraduate students through the PI's teaching of Communications Engineering, which will be updated to include quantum communications, with a direct link to this project and will serve as an introduction to the vast opportunities quantum technologies provide for the future of science and engineering.

Publications

10 25 50
 
Description EPSRC ICASE Studentship - Spin Qubits in 2D Materials
Amount £118,514 (GBP)
Funding ID EP/W522156/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 09/2021 
End 08/2025
 
Description Fibre-coupled Room Temperature Single Photon Source
Amount £130,221 (GBP)
Funding ID 130221 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 01/2021 
End 05/2022
 
Description Ultrafast Quantum Light Sources
Amount £608,772 (GBP)
Funding ID EP/S001557/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 06/2018 
End 06/2021
 
Description AegiQ Ltd 
Organisation AegiQ
Country United Kingdom 
Sector Private 
PI Contribution My research team and I have recently begun a collaboration with UK based start-up, AegiQ Ltd, whose main business is to develop single photon technology. We have recently submitted proposals to the Quantum Communications Hub Partnership Resource and as part of a large consortium to Innovate UK. Our main contribution to date is to the proposals.
Collaborator Contribution Co-writing of proposals, see above.
Impact Submission to Quantum Communications Hub Partnership Resource Fund Submission to Innovate UK
Start Year 2020
 
Description Hitachi Cambridge Laboratory 
Organisation Hitachi Cambridge Laboratory
Country United Kingdom 
Sector Private 
PI Contribution Research into quantum light sources in 2D hexagonal boron nitride.
Collaborator Contribution Research scientists at Hitachi are contributing to the scientific collaboration,in terms of expertise and access to facilities.
Impact Publication - Phonon sidebands of color centers in hexagonal boron nitride - published in Phys Rev B Publication - Optical control of the charge state of color centers in hexagonal boron nitride} - arXiv:2002.08177} - submitted to Nano Letters
Start Year 2016
 
Description Oxford Instruments Plasma Technology 
Organisation Oxford Instruments Plasma Technology
Country United Kingdom 
Sector Private 
PI Contribution Oxford Instruments have agreed to support ongoing research into spin qubits in 2D materials and will co-fund an ICASE award starting in autumn 2021.
Collaborator Contribution Oxford Instruments are supporting the ICASE. They will also provide expertise in semiconductor device processing and guidance to the project and the student will spend some of their time working on site at Oxford Instruments.
Impact ICASE award
Start Year 2020
 
Description IOP Festival Of Physics 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact An on campus event in the Forum for members of the public. Staffed a stand with activities and demos centered around light, waves, and metamaterials aimed at the general public for a poster competition.
Year(s) Of Engagement Activity 2018
 
Description International Day of Light 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Activities for International Day of Light 2019 at RAM Museum (museum takeover). 4 main areas: waveguides and endoscopy, colour and light in nature, waves and metamaterials, and VR astrophysics videos (exoplanets)
Year(s) Of Engagement Activity 2019
 
Description Royal Albert Memorial Museum (RAMM) Lates 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Stand at museum with VR headsets and light based outreach activities (wave tank, flourescence, diffraction) as part of a bigger RAMM Lates event where the museum stays open late and serves food and drink. Aimed at getting adults to look through the museum and engage with activities.
Year(s) Of Engagement Activity 2019
 
Description Simouth Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact PhD students organised and contributed to demonstrations at Sidmouth Science Festival
Year(s) Of Engagement Activity 2018