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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 ArticleDOI
TL;DR: Effective pulse compression under conditions of giant-pulse generation in a synchronously pumped parametric oscillator pumped by the second-harmonic radiation of an actively-passively mode-locked Nd;YAG laser with passive negative feedback is reported.
Abstract: We report effective pulse compression under conditions of giant-pulse generation in a synchronously pumped parametric oscillator pumped by the second-harmonic radiation of an actively-passively mode-locked Nd;YAG laser with passive negative feedback. A minimum pulse duration of 0.39 ps is achieved. The output radiation can be tuned from 0.614 to 4.16 microm.

30 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the postinflation dynamics of multilevel models involving nonminimal couplings and found that the transfer of energy from the inflaton condensate to radiative degrees of freedom, emergence of a radiation-dominated equation of state, and the onset of thermalization each consistently occur within 3$ $e$-folds after the end of inflation, largely independent of the values of the other couplings in the models.
Abstract: We have conducted extensive lattice simulations to study the postinflation dynamics of multifield models involving nonminimal couplings. We explore the parameter dependence of preheating in these models and describe the various time scales that control such nonlinear processes as energy transfer, rescattering, and the approach to radiation domination and thermalization. In the limit of large nonminimal couplings (${\ensuremath{\xi}}_{I}\ensuremath{\sim}100$), we find that efficient transfer of energy from the inflaton condensate to radiative degrees of freedom, emergence of a radiation-dominated equation of state, and the onset of thermalization each consistently occur within ${N}_{\mathrm{reh}}\ensuremath{\lesssim}3$ $e$-folds after the end of inflation, largely independent of the values of the other couplings in the models. The exception is the case of negative ellipticity, in which there is a misalignment between the dominant direction in field space along which the system evolves and the larger of the nonminimal couplings ${\ensuremath{\xi}}_{I}$. In those cases, the field-space-driven parametric resonance is effectively shut off. More generally, the competition between the scalar fields' potential and the field-space manifold structure can yield interesting phenomena such as two-stage resonances. Across many regions of parameter space, we find efficient re-scattering between the distinct fields, leading to a partial memory loss of the shape of the initial fluctuation spectrum. Despite the explosive particle production, which can lead to a quick depletion of the background energy density, the nonlinear processes do not induce any superhorizon correlations after the end of inflation in these models, which keeps predictions for cosmic microwave background observables unaffected by the late-time amplification of isocurvature fluctuations. Hence the excellent agreement between primordial observables and recent observations is preserved for this class of models, even when we consider postinflation dynamics.

30 citations

Journal ArticleDOI
TL;DR: In this paper, a theoretical method was developed to treat wideband pulsed squeezing in a traveling-wave parametric amplifier with group-velocity dispersion, and it was found that squeezing occurs over the entire phase-matching bandwidth, although the degree of squeezing decreases when the pump-pulse duration is shorter than the inverse of this bandwidth.
Abstract: A theoretical method is developed to treat wideband pulsed squeezing in a traveling-wave parametric amplifier with group-velocity dispersion. Classical stochastic wave equations that are fully equivalent to operator equations of motion are developed and solved numerically. It is found that squeezing occurs over the entire phase-matching bandwidth, although the degree of squeezing decreases when the pump-pulse duration is shorter than the inverse of this bandwidth.

30 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied the dynamics of the creation and decoherence of cat states in degenerate parametric oscillation, both with and without the Kerr nonlinearity found in recent superconducting-circuit experiments that generate cat states.
Abstract: A cat state is formed as the steady-state solution for the signal mode of an ideal degenerate parametric oscillator, in the limit of negligible single-photon signal loss. In the presence of signal loss, this is no longer true over timescales much longer than the damping time. However, for sufficient parametric nonlinearity, a cat state can still exist as a transient state. In this paper we study the dynamics of the creation and decoherence of cat states in degenerate parametric oscillation, both with and without the Kerr nonlinearity found in recent superconducting-circuit experiments that generate cat states in microwave cavities. We determine the time of formation and the lifetime of a cat state of fixed amplitude in terms of three dimensionless parameters $\ensuremath{\lambda}$, $g$, and $\ensuremath{\chi}$. These relate to the driving strength, the parametric nonlinearity relative to signal damping, and the Kerr nonlinearity, respectively. We find that the Kerr nonlinearity has little effect on the threshold parametric nonlinearity ($gg1$) required for the formation of cat states and does not significantly alter the decoherence time of the cat state, but can reduce the time of formation. The quality of the cat state increases with the value of $g$. To verify the existence of the cat state, we consider several signatures, including interference fringes and negativity. We emphasize the importance of taking into account more than one of these signatures. We simulate a superconducting-circuit experiment using published experimental parameters and find good agreement with experimental results, indicating that a nonclassical catlike state with a small Wigner negativity is generated in the experiment. Interference fringes, however, are absent, requiring higher $g$ values. Finally, we explore the feasibility of creating large cat states with a coherent amplitude of 20, corresponding to 400 photons, and study finite-temperature reservoir effects.

30 citations

Proceedings ArticleDOI
15 Jun 2008
TL;DR: In this paper, a 0.27 mW fundamental oscillator module operating at 330 GHz was presented, which is the first fundamental signal generation at submillimeter wave frequencies can be simply and reliably generated.
Abstract: In this paper, a 0.27 mW fundamental oscillator module operating at 330 GHz is presented. The MMIC in the module contains both the oscillator circuit and waveguide probes integrated on the same InP substrate. The oscillator is implemented in coplanar waveguide (CPW) technology and uses advanced high fMAX 35 nm InP HEMT transistor in a common gate configuration. The integrated radial E-plane probe has been designed to operate over a frequency range of 300–350 GHz, using WR2.2 for the input and output waveguide. A free-running frequency of 330.5 GHz has been measured by down-converting the signal to an IF frequency observable on a spectrum analyzer. This is the first oscillator module above 300 GHz and demonstrates that fundamental signal generation at submillimeter wave frequencies can be simply and reliably generated.

30 citations


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