Polarisation Entangled Photon Emitter

Quantum technologies will transform and improve crucial aspects of our life. To name a few, they will protect our privacy, and secure digital communications from any cyber attack, push the speed of computers to new levels, enable imaging the faintest objects, with applications to security and healthcare.
While few of these outcomes are moving towards commercialisation, such as quantum-secured communications, others are still far from being a robust technology.
The UK government has invested substantial resources in promoting the translation of the science available in academic institutions into technologies for the benefit of the public.
For this quantum revolution to happen, we need to combine the know-how available in the academia, the technical capabilities of our high-tech companies, and the feedback from potential users of the technology.
With this proposal, we are following this receipt, targeting the development of the first commercial source of visible, entangled photons, suitable for applications ranging from secure communication to metrology.

Entangled light is the key to unlock the possibilities offered by quantum mechanics, and is the starting point for many applications, such quantum-key distribution and quantum computing. The components required to build an entangled light source are a laser and a suitable crystal that converts the laser light into entangled photons.

Chromacity is a UK leader in the market of laser systems while Covesion is a world leader in the supply of crystals for the generation of entangled photons. We propose therefore to partner with these companies bringing our know-how in quantum optics. The University of Glasgow is indeed a leading institution in the UK, and the world, for what concern quantum optics and quantum technologies. Together, we have the production capabilities, the engineering skills, and the supply chain, to bring a visible source of entangled photons on the market.

The role of the academic team in this project is twofold. On the one hand, we shall guide the design of the optical components required to generate the entangled states, starting from the technology provided by the two partner companies. We shall exploit our experience in the generation of entangled states in a lab to inform the two companies on the best choice of the nonlinear crystals parameters, the geometry of the laser interaction with the nonlinear elements, and on the proper measurement procedure required to quantify the level of entanglement achieved. This will be, therefore, a knowledge transfer action, aimed at bringing the academic know-how into a commercial reality. On the other hand, we will test the results produced by the joint work of Chromacity and Covesion. In this scenario, the University of Glasgow team will be the beta-tester. We are indeed end-users in the potential quantum-optical market since most of our research requires entangled states to be carried on. We shall, therefore, provide our feedback to the companies, concerning performances, packaging and user-friendliness. As the research in quantum optics becomes increasingly common in academia, a growing number of researchers will look for "plug and play" sources of entangled states.

This project aims at developing a compact source of visible entangled photon pairs, and infrared correlated photon pairs.
This activity is expected to:
- Contribute to the development of secure communications at visible wavelengths. This includes, for instance, applications to free-space, satellite, and underwater quantum key distribution.
- Contribute to the development of infrared communications. This mostly addresses quantum key distribution via infrared optical fibres, at a longer wavelength concerning the current, 1550nm standard.
- Contribute to the development of quantum-enhanced metrology and imaging. This includes high-sensitivity phase measurements for academic research on the medium term, and quantum-enhanced imaging for, e.g. biological applications, on a longer run.

By combining two UK technology providers, Chromacity and Covesion, with the academic partners and end-users, we intend helping to lay the basis for the UK quantum technology, by setting up a strategic supply chain for the commercialisation of quantum states of light.