Mainz 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 73: Quantum Technologies – Solid State Systems
Q 73.3: Talk
Friday, March 6, 2026, 11:45–12:00, P 7
Toward an Efficient Quantum-Photonic Interface for Rare-Earth Ions on a Hybrid LNOI-TiO2 Platform — •Tobias Feuerbach1, Georgii Grechko1, Christopher Ng1, Roman Kolesov1, and Jörg Wrachtrup1,2 — 13rd Institute of Physics, University of Stuttgart, Germany — 2Max Planck Institute of Solid State Research, Stuttgart, Germany
Over the years rare-earth ions (REIs) have gained attention for quantum memory applications due to their telecom wavelength compatibility and exceptional coherence times. Their low photon rates, however, make cavity-enabled Purcell enhancement necessary.
Hybrid-material photonic crystal cavities (PCCs) are a promising approach for photonic integration of REIs, combining the strengths of different materials. We employ a hybrid photonic system that merges lithium niobate on insulator (LNOI), offering electro-optical tunability and scalable fabrication, with TiO2, a high-index and spin-free host for REIs, enabling scalable, tunable and efficient quantum photonic interfaces at telecom wavelength.
We compare techniques for Er3+ integration into rutile TiO2 waveguides and discuss our hybrid TiO2/LNOI process, that is based on the fabrication of freestanding TiO2 structures, Van-der-Waals bonding to x-cut LNOI and subsequent nanofabrication of the combined stack. Specifically, tunable hybrid PCCs made from TiO2/LNOI are presented. A loaded Q-factor of 42k and a tunability of 0.8 GHz/V is achieved. We use a bifocal microscope for spectral characterization, enabled by a custom freespace-to-chip coupling technique.
Keywords: Rare-earth ions (REI); Photonic crystal cavity (PCC); Hybrid material stack; Lithium niobate on insulator (LNOI); Titanium dioxide (TiO2)