Branching of stationary inversion states in a cavity-pumped paramagnetic maser amplifier

Makovetskii, D. N.; Lavrinovich, A. A.; Cherpak, N. T.

doi:10.1134/1.1259385

Cited by 3 publications

(3 citation statements)

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“…As a conclusion, let us stress once more that all the above-described SE processes are adequately described within the deterministic non-linear oscillator model (15), (16) under the double inequality 1 2 S C A V S T T T >> >> that is typical for phaser generators. For electromagnetic maser generators, which are also characterized by very low level of intrinsic radiation, condition 2 CAV S T T < ≈ is normally fulfilled [24], [25]; therefore, for this case a separate consideration is needed, which will be done in our forthcoming papers.…”

Section: S P Fmentioning

confidence: 99%

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Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave Solid-State Resonator of the Nonautonomous Phaser Generator

Makovetskii

2002

Telecom Rad Eng

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The microwave phonon stimulated emission (SE) has been investigated in a solidstate resonator of a non-autonomous acoustic quantum generator (phaser). Branching and long-time refractority (absence of the reaction on the external pulses) for deterministic chaotic and regular processes of SE were observed in the experiments with weak and strong electromagnetic pumping. The clearly depined increase of the number of the independently co-existing SE states as the pumping level rise has been observed both in physical and computer experiments. This confirms the analytical estimations of the branching density in the phase space. The nature of the SE pulses refractority is closely connected with such branching and reflects the crises of strange attractors, i.e. their collisions with unstable periodic components of the higher branches.The stimulated emission (SE) of microwave phonons has been first observed in experiments on quantum hypersound amplification, when in 1960-ies it was reported for dielectric single crystals doped with paramagnetic ions of the iron group [1] - [3]. The hypersound amplification is due to inversed population of the ion spin levels, transitions between which are allowed for the spin-phonon interaction, and is, in fact, an acoustic analog of the linear maser amplification of electromagnetic fields [4], [5].At the same time, the nature of this effect -quantum generation of microwave phonons -has remained not fully understood for a long time. There was some inertia of thinking, with analogies proposed [6] between the photon quantum generator (phaser) and electromagnetic maser generator in the same way as it had been done for amplifiers.Experimental studies of phonon SE in Ni 2+ :Al 2 O 3 and Cr 3+ :Al 2 O 3 crystals ([7] -[10]) have shown that phaser generation mechanism is actually much closer to the processes in optical lasers than those in maser generators. Really, due to very low velocity of hypersound (as compared with the velocity of light) the wavelength of acoustic SE in a microwave solid-state resonator is about 1-3 µm, i.e., it corresponds to the near-infrared range of electromagnetic radiation. The resonator Q-factor CAV

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Section: S P Fmentioning

confidence: 99%

“…As a conclusion, let us stress once more that all the above-described SE processes are adequately described within the deterministic non-linear oscillator model (15), (16) under the double inequality is normally fulfilled [24], [25]; therefore, for this case a separate consideration is needed, which will be done in our forthcoming papers.…”

Section: S P Fmentioning

confidence: 99%

Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave Solid-State Resonator of the Nonautonomous Phaser Generator

Makovetskii

2002

Telecom Rad Eng

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“…It should be emphasized that the above-described self- detunings in the phonon spectra of a nonautonomous phaser, as well as the recently observed nonlinear phenomena in electromagnetic masers [18] and autonomous acoustic quantum generators [16,19], possess an essentially nonthermal nature. Although the lower characteristic frequencies of the motions observed in this study fall within a millihertz frequency range, all these motions are related to the microwave field self-action through a spin system of a paramagnet in the absence of the socalled phonon bottleneck effect [20] (and of the resulting phonon avalanche [21]).…”

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A nonlinear dynamics of stimulated phonon emission in a nonautonomous acoustic quantum generator under superlow-frequency-modulated pumping conditions

Makovetskii

2001

Tech. Phys. Lett.

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An unusual nonlinear resonance was experimentally observed in a ruby phonon laser (phaser) operating at 9 GHz with an electromagnetic pumping at 23 GHz. The resonance is manifested by very slow cooperative self-detunings in the microwave spectra of stimulated phonon emission when pumping is modulated at a superlow frequency (less than 10 Hz). During the self-detuning cycle new and new narrow phonon modes are sequentially "fired" on one side of the spectrum and approximately the same number of modes are "extinguished" on the other side, up to a complete generation breakdown in a certain final portion of the frequency axis. This is usually followed by a short-time refractority, after which the generation is fired again in the opposite (starting) portion of the frequency axis. The entire process of such cooperative spectral motions is repeated with high degree of regularity. The self-detuning period strongly depends on difference between the modulation frequency and the resonance frequency. This period is incommensurable with period of modulation. It increases to very large values (more than 100 s) when pointed difference is less than 0.05 Hz. The revealed phenomenon is a kind of global spin-phonon self-organization. All microwave modes of phonon laser oscillate with the same period, but with different, strongly determined phase shifts -as in optical lasers with antiphase motions.PACS numbers: 05.65.+b, 42.65.Sf, 43.35.+d Phonon amplification by stimulated emission of radiation was predicted theoretically in [1] and experimentally observed in microwave range by several groups [2] in 1960-1970-th. This phenomenon is very similar to the usual paramagnetic maser gain of electromagnetic field [3,4]. But if the phonon gain is large enough to exceed the phonon losses in the solid-state resonator, the self-excitation of laser-like phonon emission is possible [5,6,7]. The wavelength of generated microwavefrequency phonons in such phonon laser lies usually in optical or near-infrared range (due to very small velocity of sound in crystals, which is about 5 orders less than the light velocity). In this sence microwave phonon laser (phaser) is more close relative of the optical laser, than terahertz phonon laser (saser), having much shorter wavelength (see [8] and references therein).Almost all early experiments with microwave phonon lasers [5,6,7] were carried out in autonomous regime, when the control parameters of the active system remain unchanged during the whole time of measurement. Various regular and chaotic processes of generation of microwave phonons in a multimode nonautonomous phaser was experimentally observed and studied [9] for ω m ≈ ω R ≈ 20-300 Hz, where ω m is the pumping modulation frequency, ω R is the relaxation frequency of a nonequilibrium autonomous acoustic system (ω R depends on pumping level). The existence of a single dominating component exp(iω R t) for the transient processes in the autonomous phonon laser reflects the collective character of a multimode stimulated emission [10] in the quantum ...

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Nonlinear dynamics of the microwave stimulated emission in dissipative paramagnetic systems

Makovetskii

Fourth International Kharkov Symposium 'Physics and Engineering of Millimeter and Sub-Millimeter Waves'. Symposium Proceedings

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Branching of stationary inversion states in a cavity-pumped paramagnetic maser amplifier

Cited by 3 publications

References 2 publications

Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave Solid-State Resonator of the Nonautonomous Phaser Generator

Nonlinear Dynamics of the Phonon Stimulated Emission in Microwave Solid-State Resonator of the Nonautonomous Phaser Generator

A nonlinear dynamics of stimulated phonon emission in a nonautonomous acoustic quantum generator under superlow-frequency-modulated pumping conditions

Nonlinear dynamics of the microwave stimulated emission in dissipative paramagnetic systems

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