Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse design of broadband and lossless topological photonic crystal
  waveguide modes   Topological photonic crystal waveguides can create edge states that may be
more robust against fabrication disorder, and can yield propagation modes below
the light line. We present a fully three-dimensional method to modify
state-of-the-art designs to achieve a significant bandwidth improvement for
lossless propagation. Starting from an initial design with a normalized
bandwidth of 7.5% (13.4 THz), the modification gives more than 100% bandwidth
improvement to 16.2% (28.0 THz). This new design is obtained using automatic
differentiation enabled inverse design and a guided mode expansion technique to
efficiently calculate the band structure and edge state modes.

18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol