FOR 1493:  Diamond Materials for Quantum Application

• Subject Area: Physics
• Term: from 2011 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 164674487

In the past couple of years solid-state quantum optics and spintronics has undergone spectacular developments(1). Achievements like coherent coupling of multiple quantum systems, spin photon entanglement or long lived quantum memories witness that the control has reached a quantum level, known so far only from atomic systems. On the other hand, versatile material properties and advanced nano-structuring brings about novel opportunities, which are unique for solid-state systems. Examples are near-field enhanced spin-photon coupling or photon-phonon coupling mediated by nano- mechanical systems(2). In contrast to atomic physics model systems, any quantum device built from solid-state materials comprises a huge number of atoms. Consequently, successful developments to solid-state quantum physics and technology rely on proper choice and design of the materials that embed the quantum degrees of freedom, thus demanding significant efforts in material science. Research in the Forschergruppe aims at exploiting the outstanding material properties of diamond for quantum technology. Defects in diamond allow for exquisite quantum control as they are embedded in a solid with intrinsically low coupling to solid-state degrees of freedom like phonons. In the past funding period, excellent progress has been made by "engineering" of single defect center properties both, with respect to spin and optical control. First steps were taken towards embedding defects in nanostructures and control units. The physics of some impurities - most notably the nitrogen vacancy (NV) and Silicon vacancy (SiV) center - are meanwhile known with such precision that they serve as a benchmark for advance electron structure calculation(3). Such knowledge gave way to new applications, e.g. for quantum networks and sensing. The proposal for the second funding period is dominated by the attempt to further integrate defects into complex periphery and developing diamond structuring onto such a level that some of the outstanding properties of bulk diamond can also be used in nanostructures. The research group strives towards continuously gathering expertise in the area of diamond growth, structuring photonics as well as quantum control. While research avenues pursued in the first funding period are continued, new directions - most importantly - engineered spin-phonon coupling will be explored. The research group now also comprises two theory projects devoted to the latter area.

• DFG Programme: Research Units

Projects

• Electrical control and read-out of color centers in diamond (Applicant Stutzmann, Martin )
• Entanglement- enhanced NV- array sensors for electric and magnetic fields (Applicants Meijer, Jan ;  Schmidt-Kaler, Ferdinand )
• Growth of ultraclean, isotopically controlled diamond films and nanoparticles with well defined single defects and atomically smooth surfaces (Applicants Krüger, Anke ;  Nebel, Christoph E. )
• Integrated Quantum Optics and Nanophotonics with Defect Centers in Nanodiamonds (Applicants Benson, Oliver ;  Weinfurter, Harald )
• Koordination der Forschungsgruppe 1493 (Applicant Wrachtrup, Jörg )
• Mechanical and Opto-mechanical Interfaces for Single Color Centers in Diamond (Applicants Becher, Christoph ;  Jelezko, Fedor ;  Plenio, Martin Bodo )
• Nearfield/dipolar interaction of defects, SET charge fluctuation measurements (Applicant Wrachtrup, Jörg )
• Tailoring light matter coupling for ultrafast quantum optics with defect centers in diamond (Applicant Bratschitsch, Rudolf )

• Spokesperson: Professor Dr. Jörg Wrachtrup