Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Absolute and relative surface profile interferometry using multiple
  frequency-scanned lasers   An interferometer has been used to measure the surface profile of generic
object. Frequency scanning interferometry has been employed to provide
unambiguous phase readings, to suppress etalon fringes, and to supersede
phase-shifting. The frequency scan has been performed in three narrow
wavelength bands, each generated by a temperature tuned laser diode. It is
shown, that for certain portions of measured object, it was possible to get
absolute phase measurement, counting all wave periods from the point of zero
path difference, yielding precision of 2.7nm RMS over 11.75mm total path
difference. For the other areas where steep slopes were present in object
geometry, a relative measurement is still possible, at measured surface
roughness comparable to that of machining process (the same 2.7nm RMS). It is
concluded, that areas containing steep slopes exhibit systematic error,
attributed to a combined factors of dispersion and retrace error.

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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph