Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Highly Sensitive and Robust Ultrahigh-Q Nanocavity on a
  Multiheterostructure Photonic Crystal   An ultrahigh-Q hybrid cavity using a graded multiheterostructure and space
modulation is designed in this work. Two high Q resonant modes exist in the
cavity and follow separate confinement mechanisms. We have demonstrated an
analytical method for designing the desired multiheterostructure. Space
modulation was used to create a robust and sensitive nanocavity. The
confinement mechanism and resonant characteristics of the resonant modes are
studied using the finite difference time domain method. We have shown that the
modes of the cavity are highly robust with respect to fabrication error. We
have also demonstrated that the nanocavity can act as a highly sensitive
refractive index sensor.

24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci