Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrabroadband nonreciprocal transverse energy flow of light in linear
  passive photonic circuits   Using a technique, analogous to coherent population trapping in an atomic
system, we propose schemes to create transverse light propagation violating
left-right symmetry in a photonic circuit consisting of three coupled
waveguides. The frequency windows for the symmetry breaking of the left-right
energy flow span over 80 nm. Our proposed system only uses linear passive
optical materials and is easy to integrate on a chip.

1
The categories of this paper are: cs
2
The categories of this paper are: math
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn