Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Attosecond Timing in Optical-to-Electrical Conversion   The most frequency-stable sources of electromagnetic radiation are produced
optically, and optical frequency combs provide the means for high fidelity
frequency transfer across hundreds of terahertz and into the microwave domain.
A critical step in this photonic-based synthesis of microwave signals is the
optical-to-electrical conversion process. Here we show that attosecond (as)
timing stability can be preserved across the opto-electronic interface of a
photodiode, despite an intrinsic temporal response that is more than six orders
of magnitude slower. The excess timing noise in the photodetection of a
periodic train of ultrashort optical pulses behaves as flicker noise (1/f) with
amplitude of 4 as/Sqrt(Hz) at 1 Hz offset. The corresponding fractional
frequency fluctuations are 1.4x10-17 at 1 second and 5.5x10-20 at 1000 seconds.
These results demonstrate that direct photodetection, as part of
frequency-comb-based microwave synthesis, can support the timing performance of
the best optical frequency standards, and thereby opens the possibility for
generating microwave signals with significantly better stability than any
existing source.

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The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
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The categories of this paper are: eess
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org