Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced spontaneous emission in photonic hypercrystals   We demonstrate a two-dimensional photonic hypercrystal that shows enhanced
spontaneous emission from its metamaterial component and light extraction
through its photonic crystal property. Spontaneous decay rate is enhanced by a
factor of 19.5 and light extraction from the HMM is enhanced by a factor of
~100.

36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol