Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A 3.5-THz, x6-Harmonic, Single-Ended Schottky Diode Mixer for Frequency
  Stabilization of Quantum-Cascade Lasers   Efficient and compact frequency converters are essential for frequency
stabilization of terahertz sources. In this paper, we present a 3.5-THz,
x6-harmonic, integrated Schottky diode mixer operating at room temperature. The
designed frequency converter is based on a single-ended, planar Schottky diode
with a sub-micron anode contact area defined on a suspended 2-$\mu$m ultra-thin
GaAs substrate. The dc-grounded anode pad was combined with the radio frequency
E-plane probe, which resulted in an electrically compact circuit. At 200 MHz
intermediate frequency, a mixer conversion loss of about 59 dB is measured and
resulting in a 40 dB signal-to-noise ratio for phase locking 3.5-THz
quantum-cascade laser. Using a quasi-static diode model combined with
electromagnetic simulations, good agreement with the measured results was
obtained. Harmonic frequency converters without the need of cryogenic cooling
will help in the realization of highly sensitive space and air-borne heterodyne
receivers.

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The categories of this paper are: hep-lat
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The categories of this paper are: stat
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex