  We present a novel method for fabricating highly customizable
three-dimensional structures hosting quantum sensors based on Nitrogen Vacancy
(NV) centers using two-photon polymerization. This approach overcomes
challenges associated with structuring traditional single-crystal quantum
sensing platforms and enables the creation of complex, fully three-dimensional,
sensor assemblies with sub-microscale resolutions (down to 400 nm) and large
fields of view (>1 mm). By embedding NV center-containing nanoparticles in
exemplary structures, we demonstrate high sensitivity optical sensing of
temperature and magnetic fields at the microscale. Our work showcases the
potential for integrating quantum sensors with advanced manufacturing
techniques, facilitating the incorporation of sensors into existing
microfluidic and electronic platforms, and opening new avenues for widespread
utilization of quantum sensors in various applications.
