Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High efficiency second harmonic generation of blue light on thin film
  lithium niobate   We demonstrate second harmonic generation of blue light on an integrated
thin-film lithium niobate waveguide and observe a conversion efficiency of
$\eta_0= 33000\%/\text{W-cm}^2$, significantly exceeding previous
demonstrations.

15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph