Freiburg 2019 – wissenschaftliches Programm
FM 84.11: Poster
Donnerstag, 26. September 2019, 16:30–18:30, Tents
Linear and Nonlinear Characterisation of Cryogenic Waveguides in Lithium Niobate — •Nina Amelie Lange1, Moritz Bartnick1, Jan Philipp Höpker1, Frederik Thiele1, Raimund Ricken2, Viktor Quiring2, Christof Eigner2, Harald Herrmann2, Christine Silberhorn2, and Tim Bartley1 — 1Mesoskopische Quantenoptik, Department Physik, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany — 2Integrierte Quantenoptik, Department Physik, Universität Paderborn, Warburger Straße 100, 33098 Paderborn, Germany
Lithium niobate is a promising platform for integrated quantum photonics. In particular, the outstanding electro-optic properties and the high second-order nonlinearity allow for high-speed modulation, polarisation conversion and sources of quantum light. These properties are well examined at room temperatures. However, many quantum optic devices, especially superconducting detectors, can only operate at cryogenic temperatures. Therefore, the properties of waveguides in lithium niobate must be investigated at temperatures of a few Kelvin. We developed some techniques to perform a linear and a nonlinear characterisation of titanium in-diffused lithium niobate waveguides inside a closed cycle cryostat. These techniques allow us to characterise the waveguide losses and the second harmonic generation at cryogenic temperatures. The examined samples show that losses and nonlinear phasematching bandwidths are not strongly affected in this temperature range. Moreover, these characterisation techniques allow to investigate the pyroelectric properties of lithium niobate.