Speaker: Prof Rachel Grange,
ETH Zurich, Department of Physics, Institute for Quantum Electronics, Optical Nanomaterial Group

Title: Nonlinear nanocrystals for electro-optic and quantum devices

Abstract:
Nonlinear and electro-optic devices are present in our daily life with many applications: light sources for microsurgery, green laser pointers, or modulators for telecommunication. Most of them use bulk materials such as glass fibres or high-quality crystals, hardly integrable or scalable. Even the fast developments of thin film lithium niobate face the challenging etching of metal-oxides¹. Therefore, the quest for a non-centrosymmetric material system, easy to fabricate and to scale up while maintaining its functionality is still ongoing². Here we will present our recent advances in top-down fabrication of lithium niobate devices and bottom-up assemblies of randomly oriented nanocrystals to produce electro-optic, nonlinear and parametric down conversion signals. First, barium titanate metalenses synthesized by a sol-gel technique will be demonstrated. Then, we will show how the electro-optic response in assembled nanostructures can be as strong as certain other perfect crystalline structure. Finally, we will generate photon pairs from free-standing lithium niobate microcubes³ and III-V nanowires at the telecommunication wavelength through the spontaneous parametric down-conversion process.

(1) Pohl, D.; Messner, A.; Kaufmann, F.; Escalé, M. R.; Holzer, J.; Leuthold, J.; Grange, R. 100-GBd Waveguide Bragg Grating Modulator in Thin-Film Lithium Niobate. IEEE Photonics Technol. Lett. 2021, 33 (2), 85–88. https://doi.org/10.1109/LPT.2020.3044648.

(2) Vogler-Neuling, V. V.; Karvounis, A.; Morandi, A.; Weigand, H.; Dénervaud, E.; Grange, R. Photonic Assemblies of Randomly Oriented Nanocrystals for Engineered Nonlinear and Electro-Optic Effects. ACS Photonics 2022, 9 (7), 2193–2203. https://doi.org/10.1021/acsphotonics.2c00081.

(3) Duong, N. M. H.; Duong, N. M. H.; Duong, N. M. H.; Saerens, G.; Saerens, G.; Timpu, F.; Buscaglia, M. T.; Buscaglia, V.; Morandi, A.; Müller, J. S.; Maeder, A.; Kaufmann, F.; Solntsev, A. S.; Grange, R.; Grange, R. Spontaneous Parametric Down-Conversion in Bottom-up Grown Lithium Niobate Microcubes. Opt. Mater. Express 2022, 12 (9), 3696–3704. https://doi.org/10.1364/OME.462981.

Biography:
Since 2021, Rachel Grange is an associate professor in integrated optics and nanophotonics in the Department of Physics at ETH Zurich. She has been assistant professor at ETH Zurich since 2015. From 2011 to 2014, she was junior group leader at the Friedrich Schiller University in Jena, Germany. Her research covers material investigations at the nanoscale, top-down and bottom-up fabricated nanostructures with metal-oxides, mainly lithium niobate and barium titanate.

Zoom:
Meeting URL: https://oist.zoom.us/j/93420646927?pwd=REFsWVg4aGl3VXVoTmNGMEpueDNvUT09

Meeting ID: 934 2064 6927
Passcode: 499044