Nonreciprocal Gain in Non-Hermitian Time-Floquet Systems

We explore the unconventional wave scattering properties of non-Hermitian systems in which amplification or damping are induced by time-periodic modulation. These non-Hermitian time-Floquet systems are capable of nonreciprocal operations in the frequency domain, which can be exploited to induce nove...

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Bibliographic Details
Published in:Physical review letters 2018-02, Vol.120 (8), p.087401-087401, Article 087401
Main Authors: Koutserimpas, Theodoros T, Fleury, Romain
Format: Article
Language:English
Subjects:
Damping
Insertion loss
Microwave amplifiers
Modulation
Wave amplification
Wave scattering
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Summary:We explore the unconventional wave scattering properties of non-Hermitian systems in which amplification or damping are induced by time-periodic modulation. These non-Hermitian time-Floquet systems are capable of nonreciprocal operations in the frequency domain, which can be exploited to induce novel physical phenomena such as unidirectional wave amplification and perfect nonreciprocal response with zero or even negative insertion losses. This unique behavior is obtained by imparting a specific low-frequency time-periodic modulation to the complex coupling between lossless resonators, promoting only upward frequency conversion, and leading to nonreciprocal parametric gain. We provide a full-wave demonstration of our findings in a one-way microwave amplifier, and establish the potential of non-Hermitian time-Floquet devices for insertion-loss free microwave isolation and unidirectional parametric amplification.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.120.087401