Year/Course: 2017-2018, Easter 2018

Single-photon source inventor : Dr. Rachel Oliver, Materials Science & Metallurgy
Single-photon detector inventor : Dr. Matthew Applegate, Physics
Mentor: Dr. Julian White

Single photon devices are being proposed for a wide variety of applications including quantum cryptography, quantum sensing and computation, satellite communications, and imaging across all length scales. Infrared single photon sources are already being used in telecommunications applications but typically need cooling to liquid Helium temperatures (4K). Moving to visible light photons would open up a new range of applications.

For the technologies to become used more widely, higher operating temperatures and lower costs are key. Both the inventors on this project have focused on making single photon creation and detection smaller, cheaper, and possible at higher temperatures.

The single-photon source has been developed over a number of years and can now produce visible light photons reliably. Current generation devices work at 220K, which can be reached by electronic cooling methods, and higher temperatures will be possible in future. The next stage is to start manufacturing the prototype device in larger volumes so that they can start to be used more widely.

The single-photon detector has been designed to work at room temperature (290K), and is far easier and less costly to manufacture than existing single-photon detecting technologies like the avalanche photodiode (APD). Owing to its unique structure, the detectors have the significant potential of attaining unrivalled performance both in terms of efficiency and bandwidth. The combination of low cost and high performance means the device should find application in a far wider range of circumstances than is currently possible with existing technologies. Cost is important because numerous detectors are expected to be needed for any given application.

The challenge for the i-Team is to investigate the market for single photon systems in the visual light range to assess the level of demand for both of these technologies. In particular, since both technologies are at an early stage of development, a key focus will be to understand the technical requirements of the target applications so that the inventors can tailor their solutions to match the market need. For example, there is always a trade-off between efficiency and temperature, so where does this balance fall in real-world applications? Is room temperature operation more important or a higher efficiency? The role of the i-Team will be to speak to relevant industry experts and provide feedback on the best future direction for these new technologies.