Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse design of lightweight broadband reflector for efficient
  lightsail propulsion   Light can exert forces on objects, promising to propel a meter-scale
lightsail to near the speed of light. The key to address many challenges in
such an ambition hinges on the nanostructuring of lightsails to tailor their
optical scattering properties. In this letter, we present a first exhaustive
study of photonic design of lightsails by applying large-scale optimization
techniques to a generic geometry based on stacked photonic crystal layers. The
optimization is performed by rigorous coupled-wave analysis amended with
automatic differentiation methods for adjoint-variable gradient evaluations.
Employing these methods the propulsion efficiency of a lightsail that involves
a tradeoff between high broadband reflectivity and mass reduction is optimized.
Surprisingly, regardless of the material choice, the optimal structures turn
out to be simply one-dimensional subwavelength gratings, exhibiting nearly 50%
improvement in acceleration distance performance compared to prior studies. Our
framework can be extended to address other lightsail challenges such as thermal
management and propulsion stability, and applications in integrated photonics
such as compact mirrors.

12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
1
The categories of this paper are: cs