Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Precise and accurate control of the ellipticity of THz radiation using a
  photoconductive pixel array   Full control of the ellipticity of broadband pulses of THz radiation, from
linear to left- or right-handed circular polarization, was demonstrated via a
4-pixel photoconductive emitter with an integrated achromatic waveplate.
Excellent polarization purity and accuracy was achieved, with Stokes parameters
exceeding 97% for linear and circular polarization, via a robust scheme that
corrected electrically for polarization changes caused by imperfect optical
elements. Further, to assess the speed and precision of measurements of the THz
polarization we introduced a new figure of merit, the standard error after one
second of measurement, found to be 0.047$^{\circ}$ for the polarization angle.

0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc