Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 66: Superconductivity: Tunneling, Josephson Junctions, SQUIDs

TT 66.1: Talk

Wednesday, March 18, 2015, 15:00–15:15, H 2053

Coherent terahertz emission from Bi₂Sr₂CaCu₂O₈ intrinsic Josephson junction stacks — •Fabian Rudau¹, Boris Gross¹, Raphael Wieland¹, Nickolay Kinev², Manabu Tsujimoto³, Min Ji^4,5, Ya Huang^4,5, Xianjing Zhou^4,5, Deyue An^4,5, Thomas Judd¹, Peiheng Wu⁵, Takeshi Hatano⁴, Huabing Wang^4,5, Valery Koshelets², Dieter Koelle¹, and Reinhold Kleiner¹ — ¹Physikalisches Institut and Center for Collective Quantum Phenomena in LISA⁺, Universität Tübingen, Tübingen, Germany — ²Kotel’nikov Institute of Radio Engineering and Electronics, Moscow, Russia — ³Kyoto University, Kyoto, Japan — ⁴National Institute for Materials Science, Tsukuba, Japan — ⁵Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China

Stacks of intrinsic Josephson junctions, made of the high temperature superconductor Bi₂Sr₂CaCu₂O₈, are promising candidates to be used as generators of electromagnetic waves in the terahertz regime, in principle allowing frequencies up to ∼10 THz. Ranging from 0.4 to 1 THz, coherent emission was detected from large, rectangular stacks, producing several tens of microwatt in power. Despite of several years of research, the mechanism of synchronizing all the junctions in the stack is still not fully understood. We investigated the heat distribution and electromagnetic standing waves in such stacks, as well as the generation of terahertz radiation, using a combination of electric transport measurements, direct radiation detection and low temperature scanning laser microscopy. Recent experimental results from our collaboration will be presented and compared to numerical simulations.