Rostock 2019 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

Q: Fachverband Quantenoptik und Photonik

Q 51: Quantum Information (Quantum Repeater) II

Q 51.5: Vortrag

Donnerstag, 14. März 2019, 15:00–15:15, S HS 002 Chemie

Towards an efficient quantum memory at telecom wavelength — •Benjamin Merkel, Pablo Cova Fariña, Natalia Herrera Valencia, Kutlu Kutluer, and Andreas Reiserer — MPI for Quantum Optics, Garching, Germany

Global quantum networks will require efficient interfaces between long-lived memory nodes and photons at a telecommunications wavelength, where loss in optical fibers is minimal. In this context, ensembles of Erbium ions doped into suited crystals are a promising candidate, as they exhibit both an optical transition at 1.5 µm and spin lifetimes exceeding 100 ms. Unfortunately, dipole-dipole interactions between neighboring Erbium ions limit the ground-state spin coherence times and restrict the experiments to crystals with low dopant concentration. This severely limits the efficiency of quantum memories. We study two approaches to overcome this challenge: First, we have assembled high-finesse cavities that enhance the optical depth 10000 fold. This should allow us to implement efficient quantum memories in crystals with extremely low dopant concentration. To facilitate cryogenic operation, the disturbance of mechanical vibrations, which are abundant in closed-cycle cryostats, were minimized by an optimization of the cavity mount. Second, we also investigate the effect of microwave pulses on ensembles of Erbium spins and explore the potential of dynamical decoupling to increase coherence times. To this end, we have implemented a resonator on a printed circuit board whose microwave field is very homogeneous over the crystal. We will present the current status of the mentioned experiments.