The Open3 Quantum – O3Q project, funded under the Quantum Aktiv programme (grant 13N15388) and carried out from 1 August 2020 to 31 July 2023, delivered a suite of low‑cost, modular hardware and educational resources that enable hands‑on quantum experiments for secondary‑school and university students. The core technical achievements centre on three experimental platforms: an optically detected magnetic resonance (ODMR) kit, a multi‑photon implementation of the BB84 quantum key distribution protocol, and a single‑photon source based on nitrogen‑vacancy (NV) centres in nanodiamonds.
The ODMR set incorporates a precisely positioned dielectric sphere whose motion is controlled by a custom electronic driver that replaces conventional piezo stages. This arrangement allows students to observe Zeeman splittings and Rabi oscillations with a simple laser‑driven system. The kit has been deployed in the physics laboratory at FH Münster, where it is used in undergraduate modules on physics engineering and quantum sensors, and in high‑school workshops. The BB84 platform consists of a compact interferometric arrangement that generates and measures polarization‑encoded photons. It has been demonstrated in a multi‑photon regime, achieving key‑rate benchmarks comparable to commercial teaching kits while remaining under €1 000 in total cost. The single‑photon source uses a 3D‑printed holder for nanodiamond samples containing NV centres. Avalanche photodiodes (APDs) are read out by a cost‑effective electronics board, and photon‑correlation timing is performed on an FPGA, yielding a coincidence‑to‑accidental ratio of roughly 10:1 under laboratory conditions. The modularity of the 3D‑printed design allows rapid reconfiguration for different experimental goals, and the entire assembly is fully open‑source, with schematics and firmware available on a public repository.
Beyond the hardware, the project produced a set of open‑educational resources (OER) and simulation tools that accompany the experimental kits. These materials include step‑by‑step guides, data‑analysis notebooks, and interactive visualisations that illustrate the underlying quantum concepts. The resources have been integrated into teacher training sessions, such as the DPG Schulungszentrum in Bad Honnef, and showcased at science outreach events including MINT‑Rallyes, open‑days at FH Münster, and Girls Days. The project’s outreach has fostered collaborations with a broad network of research groups across Germany, the Netherlands, Italy, and Lithuania, and has stimulated interest in quantum education among secondary‑school teachers.
The research outputs have been disseminated through several peer‑reviewed publications. Notable papers include “Low‑cost single‑photon source using NV‑centres in nanodiamonds” (preparation), “Modular low‑cost 3D‑printed setup for experiments with NV centres in diamond” (Eur. J. Phys. 2023, DOI 10.1088/1361‑6404/acbe7c), and a series of articles in *Physics Education* and *Naturwissenschaften im Unterricht* that describe the wave‑optics and quantum‑optics kits. The project also produced a catalogue of low‑cost wave‑optics experiments that can be assembled from 3D‑printed cubes, further extending its educational reach.
Collaboration was organised between the Fachhochschule Münster, the Institute for Didactics of Physics at the University of Münster, and the Institute for Quantum Optics at Leibniz University Hannover. Each partner contributed complementary expertise: FH Münster led the educational design and teacher training, the University of Münster provided didactic research and curriculum integration, while the Institute for Quantum Optics supplied the technical development of the quantum hardware and the design of the NV‑centre source. The project’s open‑source ethos ensures that all hardware designs, firmware, and teaching materials remain freely available for future projects, including a planned follow‑up under Quantum Aktiv II that will extend the platform to coherent control experiments.