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

arXiv:1207.1608

Time-dependent photon generation by superconducting thin-film rings irradiated by coherent microwave fields

A. I. Agafonov

Published Jul 6, 2012• 0 citations
arXivHTMLPDF

Abstract

When a thin-film ring with supercurrent is irradiated by coherent microwave field, the field induces coherent oscillations of all the Cooper pairs involved in the supercurrent. The oscillating charged condensate will emit photons with energies determined by the difference of quantized energy levels of the superconducting ring. This effect can be observed only in the rings, the thickness of which is less than both the field skin-depth and the London penetration depth. The probability of the microwave field-induced single-photon and two-photon emission is calculated. The energy - angle distributions of the emitted photons as a function of both the ring sizes and the fluxoid number trapped in the ring, are explored.

DOI
10.48550/arxiv.1207.1608

Related papers

Two-photon emission from thin superconducting rings irradiated by coherent microwave fields

A. I. Agafonov

Superconducting current instability in thin rings, irradiated by a coherent microwave electromagnetic field, is studied. On the regular circular motion of the Cooper pairs in the supercurrent states the field imposes coherent oscillations of the condensate as a whole. The oscillating condensate should emit photons with the energies determined mainly by the discrete values of the superconducting ring energy. For the first time the probability of the supercurrent decay accompanied by the two- photon emission, is derived. The ring thickness is less than both the field skin-depth and the London penetration depth. Numerical results for the energy-angular distributions of the photons, as well as the waiting time of the stimulated two-photon transition depending on both the ring sizes and fluxoid number in the initial current state, are presented.

arXiv:1112.2033•Dec 9, 2011•0 citations

Finding the boson-number distributions in superconducting thin-film rings

A. I. Agafonov

A theory of the infrared (IR)-field-induced single-photon generation by the narrow thin-film superconducting rings made of the isotropic s-wave pairing type-II superconductors is presented. It is shown that statistical measurements of the energies of photons emitted by the same current-carrying ring prepared initially in the same quantum state, allow to find the number distribution of Cooper pairs in the superconductor.

arXiv:1403.0376•International Journal of Modern Physics B•Sep 8, 2014•1 citation

Observation of macroscopic quantum effects in high T/sub c/ weak link superconducting rings

Yin Huang, Hai Jiang, A. Widom +1 more

Thin-film weak link rings were constructed using high-T/sub c/ YBaCuO superconducting thin films. The thickness of the films was 5000 AA. The weak links were biased with an AC induced current. The resulting electron pair charges on the weak links were monitored by an output voltage. The charge stored on the link (as a function of the input bias voltage) is consistent with that of a macroscopic quantum pendulum.>

IEEE Transactions on Magnetics•Sep 1, 1992•3 citations

Effects of nonequilibrium quasiparticles in a thin-film superconducting microwave resonator under optical illumination

Rangga P. Budoyo, Jared Hertzberg, C.J. Ballard +5 more

We have illuminated a thin-film superconducting Al lumped-element microwave resonator with 780 nm light and observed the resonator quality factor and resonance frequency as a function of illumination and microwave power in the 20 to 300 mK temperature range. The optically induced microwave loss increases with increasing illumination but decreases with increasing microwave power. Although this behavior may suggest the presence of optically activated two-level systems, we find that the loss is better explained by the presence of nonequilibrium quasiparticles generated by the illumination and excited by the microwave drive. We model the system by assuming that the illumination creates an effective source of phonons with energy higher than double the superconducting gap and solve the coupled quasiparticle-phonon rate equations. We fit the simulation results to our measurements and find good agreement with the observed dependence of the resonator quality factor and frequency shift on temperature, microwave power, and optical illumination. Examination of the model reveals approaches to reducing optically induced loss and improving the relaxation time of superconducting quantum devices.

Physical review. B./Physical review. B•Jan 19, 2016•16 citations

Tunable Microwave Radiation Pulse Generation by Excitation of Superconducting Closed-Loop Antennas

Timothy J. Haugan, Thomas J. Bullard, John Patrick Murphy +2 more

An electromagnetic transmitter typically consists of in dividual components such as a power supply, a pulsing source, oscillator, waveguide, and antenna. In this work we circumvent complications associated with connecting these individual components and instead combine them into a nontraditional, photonic enabled, compact transmitter device for pulse-capable and tunable, microwave radiation. This device is presently a centimeter scale, continuous, thin film superconducting ring supporting a persistent super-current charged by induction. An ultrafast laser pulse (required) illuminates the ring (either at a point or uniformly around the ring) and perturbs the super-current by the de-pairing and recombination of Copper pairs. This generates a microwave pulse where both ring and laser pulse properties dictates the radiated spectrum's shape. The transmitting device is self-contained and isolated from conductive components that are observed to interfere with the generated signal. A rich spectrum is observed that extends beyond 30 GHz (equipment limited) and illustrates the complex super-current dynamics bridging optical, THz, and microwave wavelengths.

IEEE International Conference on Plasma Science (ICOPS)•Jun 24, 2018•0 citations

Tunable Broadband Radiation Generated Via Ultrafast Laser Illumination of an Inductively Charged Superconducting Ring

John S. Bulmer, Thomas J. Bullard, Brian D. Dolasinski +6 more

An electromagnetic transmitter typically consists of individual components such as a waveguide, antenna, power supply, and an oscillator. In this communication we circumvent complications associated with connecting these individual components and instead combine them into a non-traditional, photonic enabled, compact transmitter device for tunable, ultrawide band (UWB) radiation. This device is a centimeter scale, continuous, thin film superconducting ring supporting a persistent super-current. An ultrafast laser pulse (required) illuminates the ring (either at a point or uniformly around the ring) and perturbs the super-current by the de-pairing and recombination of Cooper pairs. This generates a microwave pulse where both ring and laser pulse geometry dictates the radiated spectrum's shape. The transmitting device is self contained and completely isolated from conductive components that are observed to interfere with the generated signal. A rich spectrum is observed that extends beyond 30 GHz (equipment limited) and illustrates the complex super-current dynamics bridging optical, THz, and microwave wavelengths.

Scientific Reports•Dec 11, 2015•6 citations
When a thin-film ring with supercurrent is irradiated by coherent microwave field, the field induces coherent oscillations of all the Cooper pairs involved in the supercurrent. The oscillating charged condensate will emit photons with energies determined by the difference of quantized energy levels of the superconducting ring. This effect can be observed only in the rings, the thickness of which is less than both the field skin-depth and the London penetration depth. The probability of the microwave field-induced single-photon and two-photon emission is calculated. The energy - angle distributions of the emitted photons as a function of both the ring sizes and the fluxoid number trapped in the ring, are explored.
Superconducting current instability in thin rings, irradiated by a coherent microwave electromagnetic field, is studied. On the regular circular motion of the Cooper pairs in the supercurrent states the field imposes coherent oscillations of the condensate as a whole. The oscillating condensate should emit photons with the energies determined mainly by the discrete values of the superconducting ring energy. For the first time the probability of the supercurrent decay accompanied by the two- photon emission, is derived. The ring thickness is less than both the field skin-depth and the London penetration depth. Numerical results for the energy-angular distributions of the photons, as well as the waiting time of the stimulated two-photon transition depending on both the ring sizes and fluxoid number in the initial current state, are presented.
We have illuminated a thin-film superconducting Al lumped-element microwave resonator with 780 nm light and observed the resonator quality factor and resonance frequency as a function of illumination and microwave power in the 20 to 300 mK temperature range. The optically induced microwave loss increases with increasing illumination but decreases with increasing microwave power. Although this behavior may suggest the presence of optically activated two-level systems, we find that the loss is better explained by the presence of nonequilibrium quasiparticles generated by the illumination and excited by the microwave drive. We model the system by assuming that the illumination creates an effective source of phonons with energy higher than double the superconducting gap and solve the coupled quasiparticle-phonon rate equations. We fit the simulation results to our measurements and find good agreement with the observed dependence of the resonator quality factor and frequency shift on temperature, microwave power, and optical illumination. Examination of the model reveals approaches to reducing optically induced loss and improving the relaxation time of superconducting quantum devices.
An electromagnetic transmitter typically consists of in dividual components such as a power supply, a pulsing source, oscillator, waveguide, and antenna. In this work we circumvent complications associated with connecting these individual components and instead combine them into a nontraditional, photonic enabled, compact transmitter device for pulse-capable and tunable, microwave radiation. This device is presently a centimeter scale, continuous, thin film superconducting ring supporting a persistent super-current charged by induction. An ultrafast laser pulse (required) illuminates the ring (either at a point or uniformly around the ring) and perturbs the super-current by the de-pairing and recombination of Copper pairs. This generates a microwave pulse where both ring and laser pulse properties dictates the radiated spectrum's shape. The transmitting device is self-contained and isolated from conductive components that are observed to interfere with the generated signal. A rich spectrum is observed that extends beyond 30 GHz (equipment limited) and illustrates the complex super-current dynamics bridging optical, THz, and microwave wavelengths.
An electromagnetic transmitter typically consists of individual components such as a waveguide, antenna, power supply, and an oscillator. In this communication we circumvent complications associated with connecting these individual components and instead combine them into a non-traditional, photonic enabled, compact transmitter device for tunable, ultrawide band (UWB) radiation. This device is a centimeter scale, continuous, thin film superconducting ring supporting a persistent super-current. An ultrafast laser pulse (required) illuminates the ring (either at a point or uniformly around the ring) and perturbs the super-current by the de-pairing and recombination of Cooper pairs. This generates a microwave pulse where both ring and laser pulse geometry dictates the radiated spectrum's shape. The transmitting device is self contained and completely isolated from conductive components that are observed to interfere with the generated signal. A rich spectrum is observed that extends beyond 30 GHz (equipment limited) and illustrates the complex super-current dynamics bridging optical, THz, and microwave wavelengths.