Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 41: Poster: Quantum Sensing

FM 41.10: Poster

Dienstag, 24. September 2019, 16:30–18:30, Tents

Cavity design and simulations for a NV centre laser and laser threshold magnetometry — •Felix Hahl, Lukas Götz, and Jan Jeske — Fraunhofer-Institut für Angewandte Festkörperphysik IAF, Freiburg, Germany

The concept of laser threshold magnetometry (LTM) suggests to use nitrogen-vacancy (NV) centre 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 of fT/sqrt(Hz). The first step for realising a lasing system out of diamond was the evidence of stimulated emission of NV doped diamond. However, to achieve a lasing system the diamond needs to be highly NV doped and of a good optical quality, meaning minimizing the absorption caused by nitrogen defects and minimizing deviations from perfect single crystal structure, causing birefringence. Via simulations, we have estimated the cavity and pump power requirements to realise NV lasing based on measured material properties. We furthermore quantify how material improvements such as reduced absorption or increased NV density can significantly lower required pump powers. Based on the simulations we present a macroscopic cavity design for two purposes: precise characterisation of material through cavity-enhanced absorption spectroscopy measurements and our work towards lasing with NV centres. This is the major step towards LTM, which would strongly improve magnetic sensing for medical applications such as magnetoencephalography.