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Quantum Detectors

Periodic Reporting for period 1 - Qdet (Quantum Detectors)

Reporting period: 2017-05-01 to 2018-10-31

The problem being addressed in this project is to develop a complete prototype of a quantum sensor operating at 795 nm with near unity efficiency. State of the art detectors based on avalanche photodiodes have been heavily used over the past three decades to detect single photons; they however do not operate at the physical limit: their detection efficiency is far below unity, their time resolution is limited and their noise level is often too high. To operate a quantum memory at the single photon level as was developed within the FP7 project HANAS, excellent quantum detectors are required that can detect single photons with very high efficiencies approaching unity.
Detection of single photons is central to fundamental quantum optics experiments but also crucial for society since it is needed in a wide range of technologies such as quantum cryptography and medical imaging, all with important commercial and social applications. In HANAS, a hybrid quantum system was developed where single photons were generated with new devices based on quantum dots. The single photons were then stored in a quantum memory based on an atomic Rubidium vapour. The quantum memory represents an important addition to the quantum toolbox that will allow the operation of quantum technologies: to exchange and process information at the quantum limit, with energy consumption and data security limited by the laws of physics.
In this project the objectives were to develop, benchmark and introduce to the market a new type of detectors with applications similar to the HANAS project.
A new type of detectors recently brought to market is based on superconducting nanowires. Superconducting nanowire single photon detectors made by Single Quantum BV were developed and optimized for telecom wavelengths and used in HANAS experiments to assess possible further improvement of our quantum memory. These detectors already offered a very important advantage over the well known semiconducting devices that are widely used in research labs as well as in industrial applications in spite of the fact that they were intended for other applications at telecom wavelengths. We have already demonstrated that these detectors compete with well established semiconductor based detectors and are able to reach detection efficiencies approaching unity.
In this project a fully optimized prototype for operation at crucial atomic frequencies such as 795 nm where the D2 transition in Rubidium has already allowed numerous key experiments such as Bose Einstein condensation, high sensitivity gravimeters and atomic memories operating at the single photon level has been developed, benchmarked and brought to market by Single Quantum.

In Deliverable 1.1 the fabrication and assembly of the prototype has been described, fully optimized for the application described in this proposal.
In Deliverable 1.2 the testing and benchmarking has been described, showing that the prototype completely outperforms state of the art detectors by several orders of magnitude.

Deliverable 2.1 describes how the prototype can be brought to market and finally deliverable 2.2 describes the promising business case relating to these developments.

During our market study a lot of customers showed real interest in our product. Demonstration have been performed at members of the HANAS consortium. In addition we exhibited the prototype at more than 10 conferences and this also lead to >10 demonstrations. Finally, only 6 months of dissemination of this fully optimized product for atomic applications (i.e. a wavelength of 795 nm) has lead to 5 product sales:

1. University of Hannover, Germany;
2. National University of Singapore, Singapore;
3. University of Ottawa, Canada;
4. University of Sydney, Australia;
5. Universität Palacky, Czech Republic

The cumulative worth of these orders is 520,000 Euro.
We have fabricated, assembled and brought to market a device that goes far beyond the state of the art of current single-photon detectors for atomic applications, by outperforming them with efficiency, noise and time resolution.
General picture of the complete prototype system: an 8 channel driver on the left and the cryostat