Demonstration of an ac Josephson junction laser

• Published in: Science (American Association for the Advancement of Science) Vol. 355; no. 6328; pp. 939 - 942
• Main Authors: Cassidy, M. C., Bruno, A., Rubbert, S., Irfan, M., Kammhuber, J., Schouten, R. N., Akhmerov, A. R., Kouwenhoven, L. P.
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 03.03.2017; The American Association for the Advancement of Science
• Subjects: Active control; Circuits; Coherence; Dissipation; Electronic devices; Electronic equipment; Holes; Integration; Josephson effect; Josephson junctions; Lasers; Lasing; Microwave radiation; Microwaves; Nonlinear systems; Nonlinearity; Photons; Quantum computing; Quantum theory; Superconductivity
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aah6640

Superconducting electronic devices have reemerged as contenders for both classical and quantum computing due to their fast operation speeds, low dissipation, and long coherence times. An ultimate demonstration of coherence is lasing. We use one of the fundamental aspects of superconductivity, the ac Josephson effect, to demonstrate a laser made from a Josephson junction strongly coupled to a multimode superconducting cavity. A dc voltage bias applied across the junction provides a source of microwave photons, and the circuit’s nonlinearity allows for efficient down-conversion of higher-order Josephson frequencies to the cavity’s fundamental mode. The simple fabrication and operation allows for easy integration with a range of quantum devices, allowing for efficient on-chip generation of coherent microwave photons at low temperatures.