Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mid-infrared nonlinear optics in thin-film lithium niobate on sapphire   Periodically poled thin-film lithium niobate (TFLN) waveguides have emerged
as a leading platform for highly efficient frequency conversion in the
near-infrared. However, the commonly used silica bottom-cladding results in
high absorption loss at wavelengths beyond 2.5 $\mu$m. In this work, we
demonstrate efficient frequency conversion in a TFLN-on-sapphire platform,
which features high transparency up to 4.5 $\mu$m. In particular, we report
generating mid-infrared light up to 3.66 $\mu$m via difference-frequency
generation of a fixed 1-$\mu$m source and a tunable telecom source, with
normalized efficiencies up to 200%/W-cm$^2$. These results show
TFLN-on-sapphire to be a promising platform for integrated nonlinear
nanophotonics in the mid-infrared.

25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con