Perspectives for Color Center-Based Nano-Sensing

Individual color centers offer unique capabilities as versatile, nanoscale sensors. Most of these sensing capabilities rely on their electronic spin and its optical state read-out. Consequently, efficiently collecting color center fluorescence is important. For scanning probe-based sensing and imaging, we incorporate color centers close to the apex of conically shaped nanopillars. These nanostructures, manufactured in sophisticated top-down processes [1], enable scanning color centers near a sample and enhance fluorescence collection [2]. We also investigate the coupling of excitation laser light with different laser wavelengths into various nanopillar types and find significant enhancements of the excitation fields in the nanopillars [3].<br/>We furthermore optimize color center-based sensing via optimal control approaches [4] and novel sensing modalities: Using numerical methods, we optimize spin manipulation via shaping microwave pulses and spin initialization using laser pulses with optimized duration and intensity. While magnetic sensing is our main application field, novel approaches to color center-based sensing are evolving using near field processes such as Förster resonance energy transfer (FRET). We recently realized FRET between nitrogen vacancy (NV) centers and a luminescent two-dimensional material, namely WSe₂ [5]. We will discuss recent advances in this field including approaches to manufacture hybrid nanostructures consisting of diamond and two-dimensional materials.<br/>[1] M. Radtke et al. Micromachines, 10, 718 (2019)<br/>[2] P. Fuchs et al., New Journal of Physics, 20, 125001 (2018)<br/>[3] A. Hochstetter and E. Neu, AIP Advances, 11, 065006 (2021)<br/>[4] P. Rembold et al., AVS Quantum Science <b>2</b>, 024701 (2020)<br/>[5] R. Nelz et al. Adv. Quantum Techn. 3, 1900088 (2019)