Q.Link.X

Color centers in diamond have the advantages of long quantum memory coherence times of electron and core spins in connection with efficient optical transitions, functioning as an interface to photons for the transfer of quantum information. The interface to photons is either facilitated by a combination of micro waves- and optical transitions (nitrogen-vacancy centers, NV centers) or by a pure optical spin-control (silicon-vacancy centers, SiV centers).  Diamond as a solid state platform provides the advantage of an “on-chip” integration with photonic elements for an aimed enhancement of the spin-light interaction. The goal of the diamond subproject from the group of apl. Prof. Dr. Cyril Popov is the realization of diamond-based photonic structures (nanopillars, photonic crystals, wave guides) with the help of electron beam lithography and reactive ion etching. These mentioned structures will be coupled with color centers (NV and SiV) to increase the photon collection efficiency. To achieve this, implantation masks will be developed for the deterministic implantation of nitrogen or silicon and hence for the resulting creation of color centers. An integration of the photonic structures with metal electrodes and antennas will enable the coherent manipulation and efficient read-out of the spin state. The structures will serve as spin-photon interfaces as well as components of a quantum memory for investigations by Q.Link.X project partners.

Pro­ject Part­ners

  • Prof. Dr. C. Becher, University Saarbrücken 
  • Prof. Dr. J. Wrachtrup / Dr. I. Gerhardt, University Stuttgart
  • Prof. Dr. D. Hunger, Karlsruher Institute for Technology (KIT) 
  • Prof. Dr. O. Benson / Prof. Dr. U. Ramelow, HU Berlin
  • Prof. Dr. F. Jelezko / Prof. Dr. A. Kubanek / Prof. Dr. M. Plenio, University Ulm
  • Prof. Dr. F. Schmidt-Kaler, University Mainz
  • Prof. Dr. C. Silberhorn, University Paderborn
  • Prof. Dr. R. Freund , Heinrich Hertz Institute Berlin (HHI)

Pic­ture gal­lery

Figure 1: a) Scheme of the QR cell, in which two NV centers form the stationary quantum bits. b) For the emission of photons an optical transition is utilized, which entangles the polarization of the photon with the electron spin (blue). After photon detection (1), the electron spin state is transferred to the core spin memory (red) featuring a longer coherence time (2). Another photon from the second NV center is sent to Bob (3) as well with a subsequent transmission to a core spin in case of success (4). A Bell-measurement of the core spin (5) and a message to Bob conclude the protocol (6). c) Level scheme of a NV center combined with a neighboring 13C core spin. The optical transitions (red) for a creation of spin-photon entanglement as well as the radio frequency transitions for transmission to the core spin (green) are depicted. d) Scheme of a QR segment based on SiV centers for the creation of an entangled state of two stationary quantum bits by Bell-measurements of photons entangled with intern memory states.
Figure 1: a) Scheme of the QR cell, in which two NV centers form the stationary quantum bits. b) For the emission of photons an optical transition is utilized, which entangles the polarization of the photon with the electron spin (blue). After photon detection (1), the electron spin state is transferred to the core spin memory (red) featuring a longer coherence time (2). Another photon from the second NV center is sent to Bob (3) as well with a subsequent transmission to a core spin in case of success (4). A Bell-measurement of the core spin (5) and a message to Bob conclude the protocol (6). c) Level scheme of a NV center combined with a neighboring 13C core spin. The optical transitions (red) for a creation of spin-photon entanglement as well as the radio frequency transitions for transmission to the core spin (green) are depicted. d) Scheme of a QR segment based on SiV centers for the creation of an entangled state of two stationary quantum bits by Bell-measurements of photons entangled with intern memory states.