Title: Demonstration of an ac Josephson junction laser,
Abstract: Superconducting electronic devices have re-emerged 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 multi-mode superconducting cavity. A dc voltage bias to
the junction provides a source of microwave photons, while the circuit's
nonlinearity allows for efficient down-conversion of higher order Josephson
frequencies down 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.