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Gunn Oscillator for Local Acoustic Transducers

IP.com Disclosure Number: IPCOM000084727D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 35K

Publishing Venue

IBM

Related People

Fang, FF: AUTHOR [+2]

Abstract

A Gunn oscillator can be used as a matrix addressable and/or beam steerable acoustic transducer for storage of a plurality of "lines" of information in a polarization "echo" storage medium.

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Gunn Oscillator for Local Acoustic Transducers

A Gunn oscillator can be used as a matrix addressable and/or beam steerable acoustic transducer for storage of a plurality of "lines" of information in a polarization "echo" storage medium.

This description is divided into two parts having to do with the use of Gunn oscillators, for the purpose of generating high-frequency acoustic waves with logic type voltage pulses over a well-controlled area of the surface of a polarization echo shortage medium. I. Mechanical Coupling.

Hayakawa et al, Appl. Phys. Letters 14, 9 (1969), have shown that the coupling of the high-electric field domain to the lattice in a Gunn oscillator causes a lattice deformation via the piezoelectric effect, which can be coupled to a nonpiezoelectric medium so as to launch an acoustic wave in the medium. It is proposed that this transducer be used in a matrix addressable form to launch acoustic waves from different parts of the surface into a polarization echo material, e.g., CdS, as shown in Fig. 1.

Application of square-wave voltage pulses to an individual Gunn oscillator causes a succession of high-field domains to propagate in the direction of the voltage gradient. These domains couple piezoelectrically to the lattice of the oscillator, thereby producing a deformation which mechanically couples to the storage medium for launching an acoustic wave.

The information in the acoustic wave is stored in the storage medium when the pump cavity is excited with microwaves at the frequency of the acoustic wave. The frequency of the acoustic wave is determined by the oscillation frequency of the oscillator, as shown by Lee and White, Appl. Phys, Letters 16, 343 (1970).

Addressing different oscillators mounted on the surface of the storage medium of Fig. 1 allows localized sources of acoustic waves. Thus, as many "lines" of information as oscillators can be addressed into the storage medium. Readout of the information on a given line is obtained by addressing the given oscillator with a read pulse that propagates into the storage medium to excite the stored information, which is read out as a microwave current in the "pump" cavity.

The information is introduced in the form of acoustic waves into the st...