Freiburg 2019 – scientific programme

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FM: Fall Meeting

FM 41: Poster: Quantum Sensing

FM 41.8: Poster

Tuesday, September 24, 2019, 16:30–18:30, Tents

NV-doped diamond for ultrasensitive laser threshold magnetometry — Felix Hahl, Tingpeng Luo, Lukas Götz, Julia Langer, Volker Cimalla, and •Jan Jeske — Fraunhofer-Institut für Angewandte Festkörperphysik (IAF), Tullastr. 72, 79108 Freiburg, Germany

The concept of laser threshold magnetometry (LTM) suggests using nitrogen-vacancy (NV) centres in diamond as a laser medium to realise a magnetic-field dependent laser output and laser threshold. This could improve the sensitivity significantly to a theoretical shot-noise limit with NV-doped bulk diamond rivalling the best current sensors. While the evidence of stimulated emission in NV doped diamond is further motivation, an NV laser poses strong material demands.

We performed theoretical calculations of the laser threshold, required pump power and loss rates and identified high NV density, combined with low absorption and birefringence the major challenges in the material properties of NV diamond for LTM. In order to tackle these we combine characterization methods of absorption, birefringence, nitrogen concentration and NV spin properties with chemical vapour deposition (CVD) growth of diamond and have preliminary results on highly nitrogen-doped CVD diamonds.

Based on our simulations we furthermore developed a cavity design with a geometry to minimize power requirements for lasing. The cavity is designed to characterize diamond samples through cavity loss rates, measure amplification and work towards lasing with NV centres.