Physical Foundations of IT Security Team: Labs & Techniques

Photonic quantum memories are devices that can store single photon in a quantum coherent fashion. They are so far missing key components for the second quantum revolution and enable a plethora of novel applications. For example, quantum networks promise provable security in communication and also the possibility for connecting quantum computers and simulators for calculations on distributed machines. We focus on quantum memories implemented in room temperature alkaline vapor, a robust platform that promises suitability not only for applications on ground, but also on satellites.

Reference:

J. Wolters et al.,“Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons.”, Phys. Rev. Lett. 119, 060502 (2017).

Single photon sources

Single photon sources are devices that emit one, and only one photon at a time. As such, they are a key resource for all photonic quantum technologies. Ideally, a single-photon source should (i) emit only one photon at a time, (ii) on demand, (iii) at high generation rate and (iv) in a well-defined state in a single spatial, temporal and spectral mode. Moreover and very important, (v) different sources should be capable to generate identical photons in a reproducible fashion. Despite enormous research effort, such an ideal source does not yet exist. In our research we focus on the most advanced single photon sources that exist today, namely atom-like solid state system, e.g. semiconductor quantum dots and sources based on spontaneous parametric down conversion (SPDC).

Reference:

R. Mottola, G. Buser, C. Müller, T. Kroh, A. Ahlrichs, S. Ramelow, O. Benson, P. Treutlein, J. Wolters, “An efficient, tunable, and robust source of narrow-band photon pairs at the Rb D1 line.”, Opt. Express 28, 3159 (2020).