Rare-earth-based single photon sources for quantum telecommunication compatible with spin quantum memories

• Applicant: Dr. Roman Kolesov
• Subject Area: Experimental Condensed Matter Physics ; Synthesis and Properties of Functional Materials ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 379110753

• Final Report Year: 2021

Final Report Abstract

Within the present project, scalable architecture of photonic circuits with electro-optically tunable photonic elements made of thin lithium niobate films was developed and demonstrated. A method of activation of these elements with rare-earth elements based on ion implantation and subsequent high-temperature annealing was realized. Based on this architecture, single rare-earth emitters were detected due to their coupling with high-quality monolithic resonators and the consequent Purcell enhancement of their fluorescence. Several results which are related to the project, but can be considered as its side effects were obtained. The most important of them are: Demonstration of feasibility of rare-earth ion implantation close to a single ion level; Demonstration of sensing nearby nuclear spins by a single rare-earth ion with the potential of exploiting these spins as nuclear spin memory. I should admit, that the technological challenges of the project were underestimated. Specifically, search for efficient way of creating micro-cavities and functionalizing them with rare-earth ions took way more time and efforts than anticipated. At the same time, I would consider the project to be almost successful since individual rare-earth ions in a monolithic micro-cavity were detected. There are only a few groups across the globe capable of detecting and exploiting single rare-earth ions for quantum information applications. The results of the project suggest that the present approach can lead to fully scalable architecture for quantum information processing. Almost all necessary ingredients were demonstrated in the course of the project, namely: Activation of electro-optically tunable on-chip resonators with rare-earth ions by ion implantation. - Tunability of the cavities to compensate for manufacturing errors and for dynamic control of Purcell enhancement. - Detection of single rare-earth ions in such cavities. The missing ingredient is the electric tunability of the rare-earth emitters themselves, though the measurements by other groups suggest that this is possible. With all these individual parts demonstrated, multiple identical individually controllable single photon emitters on the same chip are possible. At the same time, LNOI provides means of creating photonic infrastructure on the very same chip for the emitted photons. In this way, the simplest approach towards quantum computing would be boson sampling.

Publications

• “Superresolution Microscopy of Single Rare-Earth Emitters in YAG and H 3 Centers in Diamond” Phys. Rev. Lett. 120, 033903 (2018)
  R. Kolesov et al.
  
• “Deterministic Single-Ion Implantation of Rare-Earth Ions for Nanometer-Resolution Color-Center Generation” Phys. Rev. Lett. 123, 106802 (2019)
  K. Groot-Berning et al.
  
• “Scalable production of solid-immersion lenses for quantum emitters in silicon carbide” Appl. Phys. Lett. 117, 022105 (2020)
  F. Sardi et al.
  
• “Sensing Individual Nuclear Spins with a Single Rare-Earth Electron Spin” Phys. Rev. Lett. 124, 170402 (2020)
  T. Kornher et al.
  
• “Spectroscopy properties of a single praseodymium ion in a crystal” New J. Phys. 22 073002 (2020)
  K. Xia et al.
  
• “High-Speed Tunable Microcavities Coupled to Rare-Earth Quantum Emitters”
  K. Xia et al.