On the Possibility of Maser Action in Nuclear Quadrupole Systems

Donovan, Robert; Vuylsteke, Arthur A.

doi:10.1063/1.1735647

Cited by 2 publications

(1 citation statement)

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“…The circulator is a vital component in the reflection-type cavity maser, and one paper discussing this topic has appeared In addition, proposals have been made for a circul atorless amplifier using two balanced maser cavities and a magic tee, and for nonreciprocal cavity masers without circulators usin~ the nonreciprocal nature of the maser interactIOn process itself [Aram and Krayer , 1958;Autler, 1958 ;Strandberg and K yhl] . Proposals have also been made for radiofrequency masers using nuclear spin levels, although the numerical calculations are not encouraging, particularly at Imver frequ encies [Braunstein, 1957;Donovan and Vuylsteke, 1960].…”

Section: Discussionmentioning

confidence: 99%

URSI National Committee Report: Commission 7. Radio Electronics. 1. Parametric Amplifiers

Tien¹,

Heffner²

1960

J. RES. NATL. BUR. STAN. SECT. D. RAD. PROP.

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The parametric amplifier was fiJ'st introduced to the microwave field in 1957 by S uhl. In his first paper [Suhl, 1957a], he proposed an equivalent circuit for a cavity type of parametric amplifier. It consists of two resonant circui ts coupled to each other through a time-varying capacitor or inductor. The use of a ferromagnetic sample as a time-varying element was discussed. In his second paper [Subl, 1957b], he theorizes in great detail on three different possible operations of a ferromagnetic amplifier; namely (a) Electromagnetic, (b) semiclectromagnetic, and (c) magnetostatic. Tien and Suhl [1958] then worked out the traveling wave version of the parametric amplifier. In their paper a propagating circuit loaded with time-var~7 in g reactor was studied. They found that, for optimum gain and bandwidth, the following conditions must be satisfiedwhere WI, W2, and ware, respectively, the signal, idler, and pump frequencie , and {31, {32, and {3 are their phase velocities. In a later paper, Tien [1958] investigated amplification and frequency conversion of propagating circuits including bandwidth, noise figure, and circuits of opposite group velocities. An alternative derivation of Tien's gain expression was derived by Chang [1959a].The basic principles of parametric in teraction are the Manley and Rowe relations. They were discussed in a paper [Manley, 1956] published in 1956, actually earlier than Suhl's invention. It stated that power at different frequencies measured at the terminals of a nonlinear reactance must obey certain relations which bear the names of the authors. Rowe [1958 ; Manley and Rowe, 1959] later published two papers discussing, respectively, tbe mf1ll signal theory and general properties of a nonlinear elemen t. P antell [1958] al 0 studied the e n erg~r elations of f1 nonl in ear resistive clement. Some extension s or the Manley-Rowe relations have b een made by Yeh [1960] and by P. A. Sturro ck [1959], and alternative derivation have been presented by Salzberg [1957] and Weiss [1957a].An important calculation was carried out [Heffner and ,Vade, 1958] concerning noise of the parametric amplifiers. They found that noise generated in the idler circui t adds to the noise generated in the signal circuit. Under u ua] operatin g conditions, the noise figure of the parametric f1mplifi er is instead of 1 for a noiseless amplifi er. Here WI is the signal frequency and W 2, the idler frequency. The signal and the idler circuits arc assumed at the same temperature.T he parametric amplifiers so far described require it pum.p source at a freCJuency higher than that of tbe signal. A scheme was described by Bloom and Cbang [1958] in which an effective pump of frequency 2w is obtained by actually pumping at frequency w, without providing any resonant circuit at 2w. Another lOl'l-frequency pumping scheme was proposed by Hogan et aL [1958] and also independently b.y Heffner. In the latter scheme, the parametrIc amplifier involves four frequencies, and is sort of a modulator internally coupled wit...

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Section: Discussionmentioning

confidence: 99%