Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simultaneous Realization of Coherent Perfect Absorber and Laser by
  Zero-Index Media with both Gain and Loss   We investigate a unique type of zero-index medium with both gain and loss
(ZIMGL), whose effective permittivity and permeability are purely imaginary and
of opposite signs. We show analytically that, by using a slab of ZIM-GL with
equal magnitude of loss and gain, coherent perfect absorber (CPA) and laser,
i.e. the socalled CPA-laser, can be achieved simultaneously. CPA-laser has been
found previously in parity-time (PT) symmetric systems. However, the underlying
physics in a PT-symmetric system is distinct from that in a ZIM-GL. By
designing a photonic crystal (PC) composed of core-shell rods, with loss and
gain distributed in either the core or the shell, we have realized such a
ZIM-GL. The CPA-laser functionality of such a PC is also confirmed in our
numerical simulations. Our work provides a different approach for simultaneous
realization of CPA and laser besides PTsymmetric systems.

9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int