Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Journal of Applied Physics

Radiation detection from Fiske steps in Josephson junctions above 200 GHz

Matteo Cirillo, I. Modena, Fortunato Santucci, P. Carelli, Maria Gabriella Castellano, Roberto Leoni

Published Jun 15, 1993• 11 citations
Publisher

Abstract

We have measured the Josephson radiation emitted at millimeter-wave frequencies by a long Josephson junction dc-current biased on Fiske steps of the current-voltage characteristic. Our measurements demonstrate that differences between dynamic excitation generating Fiske steps and fluxon oscillations giving rise to zero-field steps in long junctions may exist. The radiation, whose maximum measured frequency is 240 GHz, is generated by an in-line junction and detected on a chip by a small planar tunnel junction. From measurements of Shapiro steps amplitude and photon-assisted tunneling steps we find that the coupled radiation has a power tunability of 350 nW and the maximum coupled power is 20 nW in a 30-Ω normal-state resistance tunnel junction.

DOI
10.1063/1.353396

Related papers

Millimeter wave generation by fluxon oscillations in a Josephson junction

Matteo Cirillo, I. Modena, P. Carelli +1 more

A small-area Josephson tunnel junction is pumped by the radiation emitted by a long Josephson junction dc biased on a zero-field singularity. Josephson constant voltage steps are observed in the current-voltage characteristic of the small junction at voltages of ±150 μV corresponding to the fundamental frequency of emission of the oscillator. The radiation also gives rise to quasiparticle steps around the gap-sum voltage of the small junction. From the measured current amplitude of the steps we estimate that the maximum power coupled to the small junction is about 90 nW.

Journal of Applied Physics•Mar 15, 1989•15 citations

Josephson Junctions as Narrow-Linewidth Tunable Microwave Oscillators

O. A. Levring, Matteo Cirillo, Bjørn Dueholm +6 more

Extensive measurements of radiation emitted from long Josephson junctions d.c.-current biased on zero-field and Fiske-steps are reported. The measurements were made in the band 8-10 GHz on long Nb-Nb oxide-Pb overlap tunnel junctions with the lengths 0.5 mm and 1.0 mm having fundamental frequencies of 10 GHz and 5 GHz, respectively. Depending on the fundamental frequency of the junction 1st or 2nd harmonic detection was employed. In the fundamental scheme the frequency f n vs. the d.c.-voltage V n along the steps follows a modified Josephson voltage/frequency relation f n / V n = 2 e/nh , where n is the step-number n = 1, 2, 3,... for Fiske-steps and n = 2, 4, 6,... for zero-field steps. On a given step the frequency could be tuned (200-500 MHz) by varying the bias point. The linewidth was measured to be less than 5 kHz. All the observed phenomena are consistent with a novel unified dynamic bunched fluxon model applicable to both zero-field and Fiske-steps and are in good agreement with recent numerical solutions of the perturbed sine-Gordon equation with proper boundary conditions. Taking advantage of operation on higher order steps and strong harmonic generation the present upper frequency limit for the Josephson fluxon oscillator is above 200 GHz. The maximum power observed so far is only 5 pW, but the estimated available power is of the order 1 μW, which is quite sufficient to pump other Josephson devices.

Physica Scripta•Jun 1, 1982•5 citations

Coupling of long Josephson junction oscillators at millimeter-wave frequencies

Matteo Cirillo, Fortunato Santucci, P. Carelli +2 more

The authors report on results of phase-locking experiments in a system composed of two long Josephson junctions oscillating at millimeter-wave frequencies. The effects of the coherent behavior of the two junctions are visible on the current-voltage characteristic of the long junctions and in the power enhancement effects observed on the current-voltage characteristic of a detector junction. It is shown that is possible to couple two long junctions in such a way that the enhanced radiation can be transmitted to other devices. Results from another mode of operation of the long Josephson junction as an oscillator are also presented. This mode is based on magnetic-field-induced singularities in long junctions (Fiske steps) generated by the interaction of the cavity modes of the junction seen as an open-ended transmission line and the Josephson oscillations. This mode has given very promising results above 200 GHz, where a power of 20 nW was coupled in a 30- Omega normal state resistance tunnel junction.>

IEEE Transactions on Applied Superconductivity•Mar 1, 1993•3 citations

Experiments on tunable Josephson millimeter-wave oscillators

Matteo Cirillo, I. Modena, P. Carelli +3 more

The coupling of millimeter-wave radiation from a long Josephson junction to a small-area junction is discussed. The coupling is obtained by means of thin-film technology and the design parameters allowing radiation coupling are discussed. Since the frequency of the oscillator radiation is smaller than the plasma frequency of the detector junction, the latter shows evidence of chaotic dynamics in the current-voltage characteristic. However, very stable zero-crossing bias steps appear for high values of the applied radiation power. The tunability of the oscillator power allows measuring the dependence of the detector critical current on the external radiation to be measured; from this measured dependence and from the observed amplitude of the photon-assisted tunneling steps it is estimated that maximum coupled power is the range of tens of nanowatts.

IEEE Transactions on Magnetics•Mar 1, 1991•4 citations

Radiation power and linewidth of a semifluxon-based Josephson oscillator

M. Paramonov, M. Yu. Fominsky, V. P. Koshelets +4 more

We demonstrate a high-frequency generator operating at ∼200 GHz based on flipping a semifluxon in a Josephson junction of moderate normalized length. The semifluxon spontaneously appears at the π discontinuity of the Josephson phase artificially created by means of two tiny current injectors. The radiation is detected by an on-chip detector (tunnel junction). The estimated radiation power (at the detector) is ∼8 nW and should be compared with the dc power of ∼100 nW consumed by the generator. The measured radiation linewidth, as low as 1.1 MHz, is typical for geometrical (Fiske) resonances, although we tried to suppress such resonances by placing well-matched microwave transformers at its both ends. Making use of a phase-locking feedback loop, we are able to reduce the radiation linewidth to less than 1 Hz measured relative to the reference oscillator and defined just by the resolution of our measurement setup.

arXiv:1311.5922•Applied Physics Letters•Feb 10, 2014•2 citations

On and off-chip detection of radiation from HTS Josephson junction arrays

Kiejin Lee, Ienari Iguchi, K. Y. Constantinian

We have investigated the mutual phase interaction between a single detector junction and a phase-locked three-junction array of high-T/sub c/ Josephson junctions. The YBCO Josephson junctions were fabricated on a MgO bicrystal substrate. In the array junction structure, the dc bias current was fed to the junction array having parallel geometry with each pair of junctions shunted by a superconducting coplanar microstrip superconducting loop. The configuration of bias leads was a series connection of interlocking dc SQUIDs geometry which enables all junctions to oscillate at the same frequency. We measured the radiation power of a Josephson-junction array using an off-chip coupled to a radiometer and on-chip coupled to a single junction from centimeter- to millimeter-wave ranges. Clear self-induced Shapiro steps were observed in the current-voltage curves of the detector junction. The power transfered to the single detector junction was estimated from the modulation of Shapiro step height. The maximum detected power level was about 7 nW at frequency 150-250 GHz. The Josephson oscillation power excited the resonant mode coupled to the coplanar microstrip loops.

IEEE Transactions on Applied Superconductivity•Jun 1, 1999•1 citation
We have measured the Josephson radiation emitted at millimeter-wave frequencies by a long Josephson junction dc-current biased on Fiske steps of the current-voltage characteristic. Our measurements demonstrate that differences between dynamic excitation generating Fiske steps and fluxon oscillations giving rise to zero-field steps in long junctions may exist. The radiation, whose maximum measured frequency is 240 GHz, is generated by an in-line junction and detected on a chip by a small planar tunnel junction. From measurements of Shapiro steps amplitude and photon-assisted tunneling steps we find that the coupled radiation has a power tunability of 350 nW and the maximum coupled power is 20 nW in a 30-Ω normal-state resistance tunnel junction.
A small-area Josephson tunnel junction is pumped by the radiation emitted by a long Josephson junction dc biased on a zero-field singularity. Josephson constant voltage steps are observed in the current-voltage characteristic of the small junction at voltages of ±150 μV corresponding to the fundamental frequency of emission of the oscillator. The radiation also gives rise to quasiparticle steps around the gap-sum voltage of the small junction. From the measured current amplitude of the steps we estimate that the maximum power coupled to the small junction is about 90 nW.
Extensive measurements of radiation emitted from long Josephson junctions d.c.-current biased on zero-field and Fiske-steps are reported. The measurements were made in the band 8-10 GHz on long Nb-Nb oxide-Pb overlap tunnel junctions with the lengths 0.5 mm and 1.0 mm having fundamental frequencies of 10 GHz and 5 GHz, respectively. Depending on the fundamental frequency of the junction 1st or 2nd harmonic detection was employed. In the fundamental scheme the frequency f n vs. the d.c.-voltage V n along the steps follows a modified Josephson voltage/frequency relation f n / V n = 2 e/nh , where n is the step-number n = 1, 2, 3,... for Fiske-steps and n = 2, 4, 6,... for zero-field steps. On a given step the frequency could be tuned (200-500 MHz) by varying the bias point. The linewidth was measured to be less than 5 kHz. All the observed phenomena are consistent with a novel unified dynamic bunched fluxon model applicable to both zero-field and Fiske-steps and are in good agreement with recent numerical solutions of the perturbed sine-Gordon equation with proper boundary conditions. Taking advantage of operation on higher order steps and strong harmonic generation the present upper frequency limit for the Josephson fluxon oscillator is above 200 GHz. The maximum power observed so far is only 5 pW, but the estimated available power is of the order 1 μW, which is quite sufficient to pump other Josephson devices.
The authors report on results of phase-locking experiments in a system composed of two long Josephson junctions oscillating at millimeter-wave frequencies. The effects of the coherent behavior of the two junctions are visible on the current-voltage characteristic of the long junctions and in the power enhancement effects observed on the current-voltage characteristic of a detector junction. It is shown that is possible to couple two long junctions in such a way that the enhanced radiation can be transmitted to other devices. Results from another mode of operation of the long Josephson junction as an oscillator are also presented. This mode is based on magnetic-field-induced singularities in long junctions (Fiske steps) generated by the interaction of the cavity modes of the junction seen as an open-ended transmission line and the Josephson oscillations. This mode has given very promising results above 200 GHz, where a power of 20 nW was coupled in a 30- Omega normal state resistance tunnel junction.>
The coupling of millimeter-wave radiation from a long Josephson junction to a small-area junction is discussed. The coupling is obtained by means of thin-film technology and the design parameters allowing radiation coupling are discussed. Since the frequency of the oscillator radiation is smaller than the plasma frequency of the detector junction, the latter shows evidence of chaotic dynamics in the current-voltage characteristic. However, very stable zero-crossing bias steps appear for high values of the applied radiation power. The tunability of the oscillator power allows measuring the dependence of the detector critical current on the external radiation to be measured; from this measured dependence and from the observed amplitude of the photon-assisted tunneling steps it is estimated that maximum coupled power is the range of tens of nanowatts.
We demonstrate a high-frequency generator operating at ∼200 GHz based on flipping a semifluxon in a Josephson junction of moderate normalized length. The semifluxon spontaneously appears at the π discontinuity of the Josephson phase artificially created by means of two tiny current injectors. The radiation is detected by an on-chip detector (tunnel junction). The estimated radiation power (at the detector) is ∼8 nW and should be compared with the dc power of ∼100 nW consumed by the generator. The measured radiation linewidth, as low as 1.1 MHz, is typical for geometrical (Fiske) resonances, although we tried to suppress such resonances by placing well-matched microwave transformers at its both ends. Making use of a phase-locking feedback loop, we are able to reduce the radiation linewidth to less than 1 Hz measured relative to the reference oscillator and defined just by the resolution of our measurement setup.
We have investigated the mutual phase interaction between a single detector junction and a phase-locked three-junction array of high-T/sub c/ Josephson junctions. The YBCO Josephson junctions were fabricated on a MgO bicrystal substrate. In the array junction structure, the dc bias current was fed to the junction array having parallel geometry with each pair of junctions shunted by a superconducting coplanar microstrip superconducting loop. The configuration of bias leads was a series connection of interlocking dc SQUIDs geometry which enables all junctions to oscillate at the same frequency. We measured the radiation power of a Josephson-junction array using an off-chip coupled to a radiometer and on-chip coupled to a single junction from centimeter- to millimeter-wave ranges. Clear self-induced Shapiro steps were observed in the current-voltage curves of the detector junction. The power transfered to the single detector junction was estimated from the modulation of Shapiro step height. The maximum detected power level was about 7 nW at frequency 150-250 GHz. The Josephson oscillation power excited the resonant mode coupled to the coplanar microstrip loops.