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Parametric oscillator

About: Parametric oscillator is a research topic. Over the lifetime, 5836 publications have been published within this topic receiving 95631 citations. The topic is also known as: Parametric excitation.


Papers
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Journal Article
TL;DR: In this paper, it is shown that periodically modulating the transverse confinement, and thus the nonlinear interactions in the BEC, excites small amplitude longitudinal oscillations through parametric resonance.
Abstract: Faraday waves in a cigar-shaped Bose-Einstein condensate are created. It is shown that periodically modulating the transverse confinement, and thus the nonlinear interactions in the BEC, excites small amplitude longitudinal oscillations through a parametric resonance. It is also demonstrated that even without the presence of a continuous drive, an initial transverse breathing mode excitation of the condensate leads to spontaneous pattern formation in the longitudinal direction. Finally, the effects of strongly driving the transverse breathing mode with large amplitude are investigated. In this case, impact-oscillator behavior and intriguing nonlinear dynamics, including the gradual emergence of multiple longitudinal modes, are observed.

110 citations

Journal ArticleDOI
TL;DR: In this article, an impedance engineered Josephson parametric amplifier capable of providing bandwidth beyond the traditional gain-bandwidth product is presented, which is achieved by introducing a positive linear slope in the imaginary component of the input impedance seen by the Josephson oscillator using a $\lambda/2$ transformer.
Abstract: We present an impedance engineered Josephson parametric amplifier capable of providing bandwidth beyond the traditional gain-bandwidth product. We achieve this by introducing a positive linear slope in the imaginary component of the input impedance seen by the Josephson oscillator using a $\lambda/2$ transformer. Our theoretical model predicts an extremely flat gain profile with a bandwidth enhancement proportional to the square root of amplitude gain. We experimentally demonstrate a nearly flat 20 dB gain over a 640 MHz band, along with a mean 1-dB compression point of -110 dBm and near quantum-limited noise. The results are in good agreement with our theoretical model.

109 citations

Journal ArticleDOI
TL;DR: In this paper, the authors measured and modeled parametric gain and oscillation for two-crystal ring oscillators arranged for walkoff compensation, and showed how the orientation of the crystals determined the relative sign of the nonlinear mixing coefficient in the two crystals.
Abstract: We measure and model parametric gain and oscillation for two crystals arranged for walkoff compensation. We show how the orientation of the crystals determines the relative sign of the nonlinear mixing coefficient in the two crystals. This sign dramatically influences small signal gain and oscillator performance, and we show how to determine the correct crystal orientation from parametric-gain measurements. The performance of two-crystal oscillators is examined with particular attention to beam tilts, conversion efficiency, and beam quality. We find reduced efficiency and increased oscillation threshold when the coefficients have opposite signs in a two-crystal ring oscillator. Sign reversal seems to have little influence on spectral purity or far-field beam profiles when the oscillator is seeded.

109 citations

Patent
28 Apr 1992
TL;DR: In this article, a wide pulling voltage controlled crystal oscillator (12) operates at one third the transmit frequency followed by a frequency tripler/filter/amplifier chain that can be quickly switched on and off.
Abstract: An RF transceiver achieves a fast switching time between transmit and receive modes by leaving the transmit oscillator (12) on all the time. The transmit chain comprises a wide pulling voltage controlled crystal oscillator (12) that operates at one third the transmit frequency followed by a frequency tripler/filter/amplifier chain that can be quickly switched on and off. By operating the transmit oscillator at one third the transmit frequency, only the third harmonic of the oscillator falls into the sensitive receive frequency band. Further isolation during the receive mode is achieved by gating off the frequency tripler, pulling the frequency of the oscillator out of the receive band, electronically detuning the harmonic filter (16) and switching off the transmitter's power amplifier (18).

108 citations

Journal ArticleDOI
TL;DR: The scientific run of the ferromagnetic axion haloscope resulted in the best limit on dark matter axions to electron coupling constant in a frequency span of about 120 MHz, corresponding to the axion-mass range 42.4-43.1 μeV.
Abstract: A ferromagnetic axion haloscope searches for dark matter in the form of axions by exploiting their interaction with electronic spins. It is composed of an axion-to-electromagnetic field transducer coupled to a sensitive rf detector. The former is a photon-magnon hybrid system, and the latter is based on a quantum-limited Josephson parametric amplifier. The hybrid system consists of ten 2.1 mm diameter yttrium iron garnet spheres coupled to a single microwave cavity mode by means of a static magnetic field. Our setup is the most sensitive rf spin magnetometer ever realized. The minimum detectable field is $5.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}19}\text{ }\text{ }\mathrm{T}$ with 9 h integration time, corresponding to a limit on the axion-electron coupling constant ${g}_{aee}\ensuremath{\le}1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}$ at 95% C.L. The scientific run of our haloscope resulted in the best limit on dark matter axions to electron coupling constant in a frequency span of about 120 MHz, corresponding to the axion-mass range $42.4--43.1\text{ }\text{ }\ensuremath{\mu}\mathrm{eV}$. This is also the first apparatus to perform a wide axion-mass scanning by only changing the static magnetic field.

107 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202366
2022133
2021123
2020139
2019145
2018135