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Josephson emission with frequency span 1-11 THz from small Bi2Sr2CaCu2O8+δ mesa structures.

ABSTRACT: Mesa structures made of Bi2Sr2CaCu2O8+δ high-temperature superconductor represent stacks of atomic scale intrinsic Josephson junctions. They can be used for generation of high-frequency electromagnetic waves. Here we analyze Josephson emission from small-but-high mesas (with a small area, but containing many stacked junctions). We have found strong evidence for tunable terahertz emission with a good efficacy in a record high-frequency span 1-11 THz, approaching the theoretical upper limit for this superconductor. Emission maxima correspond to in-phase cavity modes in the mesas, indicating coherent superradiant nature of the emission. We conclude that terahertz emission requires a threshold number of junctions N ~ 100. The threshold behavior is not present in the classical description of stacked Josephson junctions and suggests importance of laser-like cascade amplification of the photon number in the cavity.

SUBMITTER: Borodianskyi EA

PROVIDER: S-EPMC5701082 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Josephson emission with frequency span 1-11 THz from small Bi2Sr2CaCu2O8+δ mesa structures.

Borodianskyi E A EA Krasnov V M VM

Nature communications 20171123 1

Mesa structures made of Bi2Sr2CaCu2O8+δ high-temperature superconductor represent stacks of atomic scale intrinsic Josephson junctions. They can be used for generation of high-frequency electromagnetic waves. Here we analyze Josephson emission from small-but-high mesas (with a small area, but containing many stacked junctions). We have found strong evidence for tunable terahertz emission with a good efficacy in a record high-frequency span 1-11 THz, ap ...[more]

PMID: 29170380

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