Schicht-Werk Stegemann kit
The Bremen modular kit (Stegemann et al., Eur. J. Phys. 2023) rebuilt as a professionally manufactured Schicht-Werk edition. Peer-reviewed, Class-2 laser under 1 mW (school-safe), 3D-printed mechanics, ESP32 readout with custom software. Visible ODMR signal, Zeeman splitting, all four NV orientations measurable.