Alexander Ling Group

Professor Alexander Ling is a Principal Investigator at the Centre for Quantum Technologies, and a member of the Department of Physics at the National University of Singapore. He was previously Chief Scientific Officer for the National Quantum Office, and Director of the Quantum Engineering Programme. In 2024, he was named as a Distinguished International Associate of the UK Royal Academy of Engineering. His research interests are in global quantum networks enabled with satellites, repeaters and memories. He is also co-founder of two quantum technology spinoffs.
Alexander Ling Group
Our group is working to bring optical quantum technology out of the lab and into the field – and even into orbit. Such field-tests of quantum mechanics pave the way for developing applications of quantum physics.
One of our team’s major goals is the development of complete entangled photon experiments that are palm-sized and suitably ruggedized for use on small satellites (CubeSats or larger), and other low-resource mobile platforms. This compares to typical lab-based entanglement experiments which run in a protected environment without severe space or power constraints.
For the satellite instrument development, we tie many different branches of physics together. Our work involves a lot of system design and integration, low-power radiation-tolerant electronics and elegant opto-mechanical design. For example, proton-induced displacement damage is a major concern, and team members have been both studying radiation models in space and conducting tests on devices to understand the impact of radiation on the lifetime of our experiments.
We have also pioneered the testing of quantum systems at the edge of space using high-altitude balloons. In one recent test, instruments were carried to an altitude of 37km and successfully recovered. The test data reveal that the control systems worked flawlessly and we are looking forward to more advanced field tests.
Looking to the future, we anticipate that integrated photonics will play a large role in the miniaturisation of quantum systems. Our team also has an effort aimed at studying waveguide structures as sources of quantum entanglement, as well as studying how complete experiments may be fabricated on a single chip.
Undergraduates are encouraged to join our team for exposure to cutting-edge experimental optics.
Group Members
Recent papers
Highly nondegenerate polarization-entangled photon pairs produced through noncritical phasematching in single-domain KTiOPO4
QUICK3 — Design of a satellite-based quantum light source for quantum communication and extended physical theory tests in space
Demonstration of a low loss, highly stable and re-useable edge coupler for high heralding efficiency and low g(2)(0) SOI correlated photon pair sources
A privacy-preserving publicly verifiable quantum random number generator
Polarization-encoded quantum key distribution with a room-temperature telecom single-photon emitter