An all-acoustic parametric amplifier in superfluid helium

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.346194· OSTI ID:6060006

Wright, D R ^[1]; Foster, J S ^[2]; Hadimioglu, B ^[3]; Quate, C F ^[1]

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1. Department of Applied Physics, Stanford University, Stanford, CA (USA)
2. IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, CA (USA)
3. Xerox Palo Alto Research Center, Palo Alto, CA (USA)

Studies of nonlinear acoustic interactions in superfluid helium at temperatures below 0.2 K have culminated in the construction of an all-acoustic parametric amplifier at gigahertz frequencies. This device represents the shortest wavelength parametric amplifier ever made, with signal wavelengths shorter than 1000 A and pump wavelengths shorter than 600 A. In the experiment, plane waves are mixed at a predefined angle in the superfluid helium. Two gain regimes are observed. The first regime is a noncollinear phase-matched process, in which the signal phonon stimulates decay of the pump phonon to create gain at the signal frequency. The second regime is a four-phonon collinear process, in which gain on the signal is created by the second harmonic of the pump. This four-phonon process is unusual and is shown to be a combination of three-phonon processes wherein the lack of conservation of energy and momentum in one process is mostly compensated by the other.

• OSTI ID: 6060006
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 68:9; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMPLIFICATION
AMPLIFIERS
ELECTRONIC EQUIPMENT
EQUIPMENT
EVEN-EVEN NUCLEI
FLUIDS
FREQUENCY MIXING
FREQUENCY RANGE
GAIN
GHZ RANGE
HARMONIC GENERATION
HELIUM 4
HELIUM II
HELIUM ISOTOPES
INTERACTIONS
ISOTOPES
LIGHT NUCLEI
NONLINEAR PROBLEMS
NUCLEI
PARAMETRIC AMPLIFIERS
PHONONS
QUANTUM FLUIDS
QUASI PARTICLES
SOUND WAVES
STABLE ISOTOPES
ULTRALOW TEMPERATURE