Topic
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.
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TL;DR: In this article, a theoretical study of a travelling-wave-type oscillator, which utilizes a flux flow in a long Josephson junction for use as a local oscillator in the integrated superconducting receiver system, is made.
Abstract: A theoretical study is made of a travelling‐wave‐type oscillator, which utilizes a flux flow in a long Josephson junction for use as a local oscillator in the integrated superconducting receiver system. An internal electromagnetic field of the oscillator junction in the flux‐flow state is investigated both numerically and analytically. It is shown that the voltage amplitude of the internal oscillation increases gradually in the direction of the flux flow and reaches a maximum value at the junction end. An equivalent circuit of the oscillator is also obtained, which gives dependences of the emitted radiation on frequency, magnetic field, and load. It is shown that the output power attains the value of the order of 10−6 W in the frequency range between 100 and 500 GHz, and that the output power and the radiation frequency can be controlled by both the bias voltage and the applied magnetic field. These theoretical results explain quantitatively the experimental ones with a Pb‐alloy long junction of length 24 λJ.
91 citations
TL;DR: The theory of the computer calculation of the stability of ion motion in periodic quadrupole fields is considered, and a matrix approach for the numerical solution of the Hill equation and examples of calculations of stability diagrams are described.
90 citations
TL;DR: In this paper, the authors present a systematic characterization of a flux-driven Josephson parametric amplifiers at millikelvin temperatures by two different detection techniques and observe the squeezing of vacuum fluctuations by superposing signal and idler bands.
Abstract: Josephson parametric amplifiers (JPA) are promising devices for applications in circuit quantum electrodynamics and for studies on propagating quantum microwaves because of their good noise performance. In this work, we present a systematic characterization of a flux-driven JPA at millikelvin temperatures. In particular, we study in detail its squeezing properties by two different detection techniques. With the homodyne setup, we observe the squeezing of vacuum fluctuations by superposing signal and idler bands. For a quantitative analysis, we apply dual-path cross-correlation techniques to reconstruct the Wigner functions of various squeezed vacuum and thermal states. At 10?dB signal gain, we find 4.9???0.2?dB squeezing below the vacuum. In addition, we discuss the physics behind squeezed coherent microwave fields. Finally, we analyze the JPA noise temperature in the degenerate mode and find a value smaller than the standard quantum limit for phase-insensitive amplifiers.
90 citations
TL;DR: In this paper, a wideband traveling-wave formalism for analyzing quantum mechanically a degenerate parametric amplifier was developed. But the authors focused on the effect of phase mismatching and pump quantum fluctuations on the squeezing produced by the generator.
Abstract: We develop a wideband traveling-wave formalism for analyzing quantum mechanically a degenerate parametric amplifier. The formalism is based on spatial differential equations-spatial Langevin equations-that propagate temporal Fourier components of the field operators through the nonlinear medium. In addition to the parametric nonlinearity, the Langevin equations include absorption and associated fluctuations, dispersion (phase mismatching), and pump quantum fluctuations. We analyze the dominant effects of phase mismatching and pump quantum fluctuations on the squeezing produced by a degenerate parametric amplifier.
88 citations
TL;DR: In this paper, the authors report electron spin resonance spectroscopy measurements performed at millikelvin temperatures in a custom-built spectrometer comprising a superconducting micro-resonator at 7 GHz and a Josephson parametric amplifier.
Abstract: We report electron spin resonance spectroscopy measurements performed at millikelvin temperatures in a custom-built spectrometer comprising a superconducting micro-resonator at 7 GHz and a Josephson parametric amplifier. Owing to the small ( ∼10−12λ3) magnetic resonator mode volume and to the low noise of the parametric amplifier, the spectrometer's single shot sensitivity reaches 260 ± 40 spins/echo translating into 65±10 spins/Hz for repeated acquisition.
87 citations