Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new Generation of Spectrometer Calibration Techniques based on Optical
  Frequency Combs   Typical astronomical spectrographs have a resolution ranging between a few
hundred to 200.000. Deconvolution and correlation techniques are being employed
with a significance down to 1/1000 th of a pixel. HeAr and ThAr lamps are
usually used for calibration in low and high resolution spectroscopy,
respectively. Unfortunately, the emitted lines typically cover only a small
fraction of the spectrometer's spectral range. Furthermore, their exact
position depends strongly on environmental conditions. A problem is the strong
intensity variation between different (intensity ratios {>300). In addition,
the brightness of the lamps is insufficient to illuminate a spectrograph via an
integrating sphere, which in turn is important to calibrate a long-slit
spectrograph, as this is the only way to assure a uniform illumination of the
spectrograph pupil.
  Laboratory precision laser spectroscopy has experienced a major advance with
the development of optical frequency combs generated by pulsed femto-second
lasers. These lasers emit a broad spectrum (several hundred nanometers in the
visible and near infra-red) of equally-spaced "comb" lines with almost uniform
intensity (intensity ratios typically <10). Self-referencing of the laser
establishes a precise ruler in frequency space that can be stabilized to the
10e-18 uncertainty level, reaching absolute frequency inaccuracies at the
10e-12 level per day when using the Global Positioning System's (GPS) time
signal as the reference. The exploration of the merits of this new technology
holds the promise for broad-band, highly accurate and reproducible calibration
required for reliable operation of current and next generation astronomic
spectrometers.

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The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics
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The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-th
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: econ