Radiation comb generation with extended Josephson junctions

Abstract

We propose the implementation of a Josephson radiation comb generator (JRCG) based on an extended Josephson junction subject to a time dependent magnetic field. The junction critical current shows known diffraction patterns and determines the position of the critical nodes when it vanishes. When the magnetic flux passes through one of such critical nodes, the superconducting phase must undergo a π-jump to minimize the Josephson energy. Correspondingly a voltage pulse is generated at the extremes of the junction. Under periodic driving this allows us to produce a comb-like voltage pulses sequence. In the frequency domain it is possible to generate up to hundreds of harmonics of the fundamental driving frequency, thus mimicking the frequency comb used in optics and metrology. We discuss several implementations through a rectangular, cylindrical and annular junction geometries, allowing us to generate different radiation spectra and to produce an output power up to 10 pW at 50 GHz for a driving frequency of 100 MHz.

Proximity SQUID Single-Photon Detector via Temperature-to-Voltage Conversion

“…To exploit the phase jump effect discussed in Sec. I and [19,21,22] , we consider two SNS Josephson weak links in a SQUID configuration. One of the JWLs, say junction 1, is coupled to an antenna and it is heated by the photon, as shown in Fig.…”

Josephson flux-flow oscillator: The microscopic tunneling approach

“…Apart from the example of the conventional FFO studied here, an admittedly incomplete list of the affected systems and phenomena includes detection and excitation of subterahertz sound by long Josephson junctions [119,120], Cherenkov [121,122] and exponentially shaped [92,[99][100][101] FFOs, transmission line intersections and networks [123][124][125][126][127][128], Josephson frequency comb generators [129,130], annular Josephson junction [131,132] and its variations [133][134][135], linear [136] and nonlinear [137,138] fluxon modes in 2D junctions, Josephson vortex qubits [139][140][141][142], pumps [143] and ratchets [144][145][146][147][148][149][150].…”

Microwave quantum refrigeration based on the Josephson effect

“…The dynamics of a driven SQUID can be complex and must be solved numerically. We rely on the driven resistively and capacitively shunted Josephson junction (RCSJ) equation [20][21][22] .…”

“…This corresponds to sharp voltage pulses developed across the SQUID junctions. Under this condition, a moderate frequency drive can generate from some hundreds to thousands of higher harmonics [20][21][22] . This frequency upconversion allows us to reach sufficiently high voltages and, thus, the peaks in Fig.…”

“…The structure we envision is a superconducting quantum interference device (SQUID) which allows us to control the dynamics of the macroscopic quantum phase through an externally applied time-dependent microwave magnetic field. The operating principle of this refrigeration method is based on the recent discovery that a driven SQUID can generate intense voltage pulses [20][21][22] . These voltage pulses can be used to actively transfer heat from one superconductor to the other and, therefore, to cool one of them.…”