Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic investigations of a Ti:Tm:LiNbO3 waveguide for photon-echo
  quantum memory   We report the fabrication and characterization of a
Ti$^{4+}$:Tm$^{3+}$:LiNbO$_3$ optical waveguide in view of photon-echo quantum
memory applications. In particular, we investigated room- and
cryogenic-temperature properties via absorption, spectral hole burning, photon
echo, and Stark spectroscopy. We found radiative lifetimes of 82 $\mu$s and 2.4
ms for the $^3$H$_4$ and $^3$F$_4$ levels, respectively, and a 44% branching
ratio from the $^3$H$_{4}$ to the $^3$F$_4$ level. We also measured an optical
coherence time of 1.6 $\mu$s for the $^3$H$_6\leftrightarrow{}^3$H$_4$, 795 nm
wavelength transition, and investigated the limitation of spectral diffusion to
spectral hole burning. Upon application of magnetic fields of a few hundred
Gauss, we observed persistent spectral holes with lifetimes up to seconds.
Furthermore, we measured a linear Stark shift of 25 kHz$\cdot$cm/V. Our results
are promising for integrated, electro-optical, waveguide quantum memory for
photons.

6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
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The categories of this paper are: acc-phys