Showing papers on "Parametric oscillator published in 1979"
TL;DR: In this article, a detailed study of the optimum design parameters for the LiNbO 3 parametric oscillator is presented, considering practical factors that limit OPO performance such as laser beam quality and crystal damage mechanisms.
Abstract: This paper presents a detailed study of the optimum design parameters for the LiNbO 3 parametric oscillator. Theoretical and experimental studies of the optical parametric oscillator (OPO) threshold parameters and of linewidth control are presented. Consideration is given to practical factors that limit OPO performance such as laser beam quality and crystal damage mechanisms. In addition, stable single axial mode operation is reported.
431 citations
TL;DR: In this paper, an infinite number of new invariants and related auxiliary equations for the time-dependent harmonic oscillator were derived, and the number of auxiliary equations was shown to be infinite.
180 citations
TL;DR: In this article, a minimum value is found for the force acting on an oscillator or a free particle which can be discovered by this sort of measurement, and some examples are considered.
Abstract: Quantum restrictions on the measurement of the trajectory of a harmonic oscillator are calculated by the method of path integration. A minimum value is found for the force acting on an oscillator or a free particle which can be discovered by this sort of measurement. Some examples are considered.
122 citations
TL;DR: In this article, a degenerate parametric oscillator driven by a random current additionally applied to a sinusoidal pumping current is found to exhibit a new type of oscillatory-to-nonoscillatory transition.
Abstract: A degenerate parametric oscillator which is driven by a random current additionally applied to a sinusoidal pumping current is found to exhibit a new type of oscillatory‐to‐nonoscillatory transition. This noise‐induced phase transition has a different kind of critical behavior from that observed in usual phase transitions, that is, near the threshold the variance of the fluctuating output current remains constant, however, the critical slowing‐down does occur. A stochastic equation for the parametric oscillation which includes a random force multiplied by the amplitude itself is derived and the experimental results are fully accounted for in terms of that equation.
65 citations
TL;DR: In this paper, a formalism for a time-dependent harmonic oscillator is presented and the quantum-mechanical solution is developed and the Green's function is derived, and particular examples of runaway and dissipative behavior are considered.
Abstract: A formalism for a time-dependent harmonic oscillator is presented. The quantum-mechanical solution is developed and the Green's function is derived. Particular examples of runaway and dissipative behavior are considered.
42 citations
TL;DR: In this paper, a phase transition induced by external noise was observed using a parametric oscillator driven by a random current, additionally supplied to the sinusoidal pumping current, and the phase transition was shown to be induced by an external noise source.
36 citations
Patent•
29 Oct 1979
TL;DR: In this paper, a cross-bar signal mixer with a balanced planar taper section supported upon a dielectric substrate placed across the carrier and local oscillator wave guides perpendicular to the direction of electromagnetic energy propagation is presented.
Abstract: The invention is a cross-bar signal mixer suitable for low-cost high-yield mass production. The mixer configuration consists of a balanced planar taper section supported upon a dielectric substrate placed across the carrier and local oscillator wave guides perpendicular to the direction of electromagnetic energy propagation. Beam lead mixer diodes are connected across the feed-point of the taper section. The local oscillator energy is injected in transverse electric mode relation at the junction of the two mixer diodes, thereby effectively decoupling the local oscillator from the carrier signal input. The intermediate frequency energy is abstracted from the same point as the local oscillator energy is injected and is decoupled by a low-pass filter. The local oscillator and the intermediate frequency circuits are incorporated on the same planar substrate as the carrier signal circuit and are therefore not critical in design.
22 citations
Patent•
19 Sep 1979
TL;DR: In this article, an electronically tunable oscillator comprises a transistor coupled to ground by an emitter resistor and the collector and base of the transistor are interconnected through an inductor which has a tap connected to a bypass capacitor and a B+ voltage source.
Abstract: An electronically tunable oscillator comprises a transistor coupled to ground by an emitter resistor. The collector and base of the transistor are interconnected through an inductor which has a tap connected to a bypass capacitor and a B+ voltage source. The source maintains the collector and base at the same DC potential. The collector of the transistor is coupled to a capacitance which cooperates with the inductor to provide a tuned circuit. At least part of the capacitance is provided by a varactor whose value can be controlled to determine oscillator frequency. The magnitude of the oscillator frequency is limited to two times the base to emitter voltage of the transistor and the use of the emitter resistor cooperates to minimize distortion.
21 citations
Patent•
19 Dec 1979TL;DR: In this paper, a position sensing element forms a reactance (inductive or capacitive) in the L/C tuning circuit of an oscillator, and the reactance varies as a function of the position of the sensing element relative to a predetermined object.
Abstract: A position sensing element forms a reactance (inductive or capacitive) in the L/C tuning circuit of an oscillator. The reactance varies as a function of the position of the sensing element relative to a predetermined object. This causes the resonant frequency of the oscillator to vary as a function of the position of the sensing element. The output of the oscillator is squared to provide a square wave signal, the frequency of which is a direct function of the position of the sensing element relative to the predetermined object.
19 citations
TL;DR: In this paper, the transition through resonance of a weakly nonlinear oscillator is described by Duffing's equation and the forcing frequency varies very slowly in the neighborhood of the natural frequency of the linearized equation.
Abstract: This note describes the transition through resonance of a weakly nonlinear oscillator. The oscillator is described by Duffing’s equation and the forcing frequency varies very slowly in the neighborhood of the natural frequency of the linearized equation. When the damping is sufficiently small, oscillations are excited on a wide variety of timescales.
17 citations
TL;DR: In this paper, the Lagrange multipliers associated with the cranked harmonic oscillator model are studied and the coefficient of L 1 in the minimization procedure is shown to be generally not simply equal to ω as it is usually taken.
TL;DR: In this article, the importance of phase relations for excitation of the oscillations and of nonlinearities in their stabilization was emphasized, and the experiments were so organized that the students would meet unknown phenomena and problems; actually they discovered an unexpected recurrence effect in the spring pendulum.
Abstract: Some experiments on parametric effects, to be constructed by the students themselves, are described together with the discussion and questions given. Parametric oscillations were produced on a string, in a resonance circuit and a spring pendulum. The importance of phase relations for excitation of the oscillations and of nonlinearities in their stabilization was emphasized. The experiments were so organized that the students would meet unknown phenomena and problems; actually we discovered an unexpected recurrence effect in the spring pendulum.
TL;DR: In this paper, the signal and noise properties of two basic types of externally pumped parametric amplifiers, using Josephson junctions with low capacitance, are calculated based on the conventional RSJ model of the Josephson junction.
Abstract: The signal and noise properties of two basic types of externally pumped parametric amplifiers, using Josephson junctions with low capacitance, are calculated. The first type is a single- frequency nondegenerate amplifier and second one is a two-frequency degenerate amplifier, referred to sometimes as SUPARAMP. Calculations are based on the conventional RSJ model of the Josephson junction. In contrast to the works published earlier, the most realistic open circuit approximation is used for idler combinational frequencies, as well as for the pumping frequency harmonics. A single-frequency amplifier is shown to have relatively low noise temperatures ( T_{N} \approx 25T ) at signal frequencies of the order of the Josephson junction characteristic frequency ω c . On the other hand, SUPARAMP can have much lower noise but at lower frequencies, and it behaves approximately as a usual parametric amplifier with a critical frequency \omega_{cr} \approx 0.2 \omega_{c} .
Patent•
09 Mar 1979TL;DR: In this article, the authors present a means for obtaining a high Q oscillator which is compact and adapted to be readily incorporated into known forms of microwave integrated circuits, e.g. a parametric amplifier.
Abstract: Disclosed is a means for obtaining a high Q oscillator which is compact ands adapted to be readily incorporated into known forms of microwave integrated circuits, e.g. a parametric amplifier. The oscillator which for example may comprise a pump oscillator for a parametric amplifier includes efficient means for coupling to microstrip without destroying the high Q of the oscillator circuit. The negative resistance elements which may be, for example, a Gunn diode, IMPATT diode or the like is located in a resonator cavity which is a combination of radial transmission line cavity and a rectangular waveguide cavity.
TL;DR: In this article, the eigenvalues of the radial Schrodinger equation of a rotating harmonic oscillator depending on a parameter α > 0 are shown to be independent of α and equal to integers.
TL;DR: In this paper, the authors calculate the time development of the photon distribution for the signal wave by treating both fields quantum mechanically, and show that photon-anticorrelation effects can develop if two initially coherent light fields with the frequencies ω and 2ω pass a degenerate parametric amplifier.
TL;DR: In this paper, an injection-locking configuration for high-power CO2 laser systems was proposed, which can provide emission in single axial modes on rotational transitions which can be freely selected by feeding fluencies of a few mW/cm2 at the particular transition into the oscillator cavity.
Abstract: Employing injection-locking techniques an oscillator configuration was found comprising in a simple way all the features required for fusion directed high-power CO2 laser systems. The oscillator provides emission in single axial modes on rotational transitions which can be freely selected by feeding fluencies of a few mW/cm2 at the particular transition into the oscillator cavity. In the same way simultaneous emission on selectable lines can be achieved. By the same principle the oscillator can be forced to emit in any orientation of polarization. The set up is relatively simple, the alignment rather uncritical, and the operation reliable. Gaussian-shaped nanosecond pulses with low forepulse power are produced with the help of a pulse cutter and saturable multiline absorber. The set up is described and its features are demonstrated by measurements.
TL;DR: In this article, the development of a low-noise superconducting parametric amplifier operated at liquid helium temperatures and designed for practical use with a radio telescope at 33 GHz is reported.
Abstract: Progress on the development of a low-noise superconducting parametric amplifier operated at liquid helium temperatures and designed for practical use with a radio telescope at 33 GHz is reported. Series arrays of small Pb - Pb oxide - Pb tunnel junctions ( \sim 20 \mu m × 20 μm) are coupled in a microstrip configuration and the Josephson device is operated as a reflection-type amplifier in the doubly degenerate mode. Various practical considerations in using such a devise on a telescope are reviewed. In preliminary experiments, gains of greater than 13 dB have been observed near 33 GHz.
TL;DR: In this paper, generalized Bose operators are used to reduce the general anharmonic oscillator into an harmonic oscillator with a frequency which depends on the strength of the anharmonicity (λ) and on the quantum number.
TL;DR: Using a novel feedback technique an oscillator generates nonresonant LC oscillations whose frequency increases with increasing damping of the circuit, and applications for contactless measurement of the conductivity, permeability, diameter and thickness of materials, and displacement measurements are discussed.
Abstract: Using a novel feedback technique an oscillator generates nonresonant LC oscillations whose frequency increases with increasing damping of the circuit. Applications for contactless measurement of the conductivity, permeability, diameter, and thickness of materials, and displacement measurements are discussed.
Patent•
08 May 1979
TL;DR: In this article, a transducer assembly for holding a work tool was disclosed with a variable frequency oscillator, and the oscillator swept through a spectrum of frequencies under control of oscillator control means.
Abstract: A dental handpiece is disclosed with a transducer assembly for holding a work tool which is caused to vibrate at substantially a resonant frequency by a variable frequency oscillator (20). The oscillator (20) sweeps through a spectrum of frequencies under control of oscillator control means (24). A maximum in the current flow through the transducer assembly occurs at a resonant frequency and is detected by maximum detecting means (22) which then generates a latch signal to stop the oscillator at substantially that resonant frequency. Hence the oscillator is correlated to the resonant frequency of the assembly, and subsequent changes in the loading conditions on the assembly do not affect the oscillator frequency.
TL;DR: In this paper, the quantum statistics of parametric oscillation in a medium with cubic polarization were investigated in parametric approximation, starting from an effective hamiltonian containing Bose operators of the signal, idler and pump mode and their coupling to heat baths, they obtained a c-number Fokker-Planck equation and stochastically equivalent Langevin equations.
Abstract: The quantum statistics of parametric oscillation in a medium with cubic polarization is investigated in parametric approximation. Starting from an effective hamiltonian containing Bose operators of the signal, idler and pump mode and their coupling to heat baths, we obtain a c-number Fokker-Planck equation and the stochastically equivalent Langevin equations. These equations are solved, below threshold, well above threshold and near threshold. The linewidth of the signal and idler wave and their autocorrelation and crosscorrelation functions are calculated, characteristic differences between the four-photon and the three-photon parametric oscillators are discussed. The solution of the Fokker-Planck equation near threshold for a multimode pump laser is also obtained.
15 Oct 1979
TL;DR: In this article, the diagonal density matrix elements for a dynamical subsystem which is either anharmonic or harmonic highly excited oscillator interacting with the crystal vibrations are found for the extreme case of the infinitely highly-excited oscillator.
Abstract: The diagonal density matrix elements are found for a dynamical subsystem which is either anharmonic or harmonic highly excited oscillator interacting with the crystal vibrations. For the extreme case of the infinitely highly excited oscillator the result is exact. Different limiting cases are considered. In particular for the harmonic oscillator the validity criterion for the balance equation is found.
TL;DR: In this article, the response of the single mode operating laser to the weak nonresonant field is investigated and it is found that at a certain frequency of the applied field its superposition with the response field results in amplification of applied field.
01 Mar 1979
Journal Article•
TL;DR: In this article, the authors investigate the generation of a magnetic field in a plasma acted upon by powerful radiation, which is taken to be parametric excitation of the zeroth harmonic of a nonpotential field; this harmonic increases as a result of parametric resonance of the pump wave with the Langmuir oscillations.
Abstract: We investigate the generation of a magnetic field in a plasma acted upon by powerful radiation. The generation mechanism is taken to be parametric excitation of the zeroth harmonic of a nonpotential field; this harmonic increases as a result of parametric resonance of the pump wave with the Langmuir oscillations. The estimate obtained for the nonlinear saturation level of the magnetic field points to a possibility of generating megagauss fields in a laser plasma.
TL;DR: In this paper, the influence of a static drift between electrons and ions on the evolution of parametric instabilities is considered for both the low and high frequency domains, with the ion dynamics being neglected in the high frequency susceptibility.
Abstract: The theory of parametric resonance is applied to a current‐carrying magnetized plasma. The influence of a static drift between electrons and ions on the evolution of parametric instabilities is considered for both the low‐ and high‐frequency domains, with the ion dynamics being neglected in the high‐frequency susceptibility. It is shown that static drift can stabilize or facilitate parametric growth of turbulent noise.