Alexander LING Euk Jin

PhD, National University of Singapore (2008)

Assistant Professor
Office : S15-02-03  |  Tel : (65) 6516 2985
Email : phyalej or cqtalej@nus.edu.sg

Current Research

  • My research group works to leverage optical technology for building compact, rugged & effective optical entanglement systems. Such systems are used for testing fundamental physics and demonstrating quantum-assisted applications. We work with a wide range of optical tools, and have an active interest in nonlinear optics including bulk and waveguide materials, for frequency conversion at the few photon level. Systems integration (optics, electronics & mechanical design) is a key theme of our work and undergraduate students are encouraged to take part in our projects.

  • I am currently working on a project called SPEQS (Small Photon-Entangling Quantum Systems) which is designed to incorporate photon-pair sources and detectors into a single package of 300 mililitres, capable of running off a single CR1220 battery for 3 hours. SPEQS packages are designed so that they can fit nanosatellites called CubeSats - providing a cost-effective platform for testing quantum mechanics in low earth orbit, and paving the way for long range applications of correlated, or entangled photons. As SPEQS packages are built out of commercial parts, their cost is low, and may be adopted by schools for teaching modern physics. Another active area of interest is in optical circuits built out of waveguides - such circuits are useful for a variety of quantum information tasks e.g. generating path-entangled photon states or in high-bandwidth random number generators.

Small Photon-Entangling Quantum Systems (SPEQS) require entangled photon sources in a small form factor. The source shown here can emit 1,000 entangled photon pairs a second, and is 8 cm x 1.5 cm x 1.5 cm.

Selected Publications

  1. Tan Yue Chuan, Rakhitha Chandrasekara, Cliff Cheng and Alexander Ling, Silicon avalanche photodiode operation and lifetime analysis for small satellites, Optics Express, Vol. 21, Issue 14, pp. 16946-16954, 2013

  2. William Morong, Daniel Oi and Alexander Ling, Quantum Optics for Space Platforms, Optics and Photonics News, Vol. 23, 42, 2012

  3. Sergey V. Polyakov, Andreas Muller, Edward B. Flagg, Alexander Ling, Natalia Borjemscaia, Edward V. Buren, Alan Migdall and Glenn S. Solomon, Coalescence of single photons emitted by disparate single-photon sources: the example of InAs Quantum Dots and Parametric Down Conversion Sources, Physical Review Letters, Vol. 107, 157402, 2011

  4. Sergey V. Polyakov, Andreas Muller, Edward B. Flagg, Alexander Ling, Alan Migdall and Glenn S. Solomon, Two photon interference from separate quantum dots, Physical Review Letters, Vol. 104, 137401, 2010

  5. Aaron Pearlman, Alexander Ling, Elizabeth Goldschmidt, Jingyun Fan and Alan Migdall, Enhancing image contrast using coherent states and photon number resolving detectors, Optics Express, Vol. 18, 6033, 2010

  6. Zachary H. Levine, Jun Chen, Jingyun Fan, Alexander Ling and Alan Migdall Heralded, Pure-state single-photon source based on a Potassium Titanyl Phosphate waveguide, Optics Express, Vol. 18, 3708, 2010

Affiliations & Links