Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of the Dissipative Parametric Gain in a GaAs/AlGaAs
  Superlattice   Parametric generation of oscillations and waves is a paradigm, which is known
to be realized in various physical systems. Unique properties of quantum
superlattices allow to investigate high-frequency phenomena induced by the
Bragg reflections and negative differential velocity of the miniband electrons.
Effects of parametric gain in the superlattices at different strengths of
dissipation have been earlier discussed in a number of theoretical works, but
their experimental demonstrations are so far absent. Here, we report on the
first observation of the dissipative parametric generation in a subcritically
doped GaAs/AlGaAs superlattice subjected to a dc bias and a microwave pump. We
argue that the dissipative parametric mechanism originates from a periodic
variation of the negative differential velocity. It enforces excitation of slow
electrostatic waves in the superlattice which provide a significant enhancement
of the gain coefficient. This work paves the way for a development of a
miniature solid-state parametric generator of GHz\nobreakdash--THz frequencies
operating at room temperature.

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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin