Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Coupling interlayer excitons to whispering gallery modes in van der
  Waals heterostructures   Van der Waals heterostructures assembled from two-dimensional materials offer
a promising platform to engineer structures with desired optoelectronic
characteristics. Here we use waveguide-coupled disk resonators made of
hexagonal boron nitride (h-BN) to demonstrate cavity-coupled emission from
interlayer excitons of a heterobilayer of two monolayer transition metal
dichalcogonides. We sandwich a MoSe$_{\rm 2}$ - WSe$_{\rm 2}$ heterobilayer
between two slabs of h-BN and directly pattern the resulting stack into
waveguide-coupled disk resonators. This enables us to position the active
materials into regions of highest optical field intensity, thereby maximizing
the mode overlap and the coupling strength. Since the interlayer exciton
emission energy is lower than the optical band gaps of the individual
monolayers and since the interlayer transition itself has a weak oscillator
strength, the circulating light is only weakly reabsorbed, which results in an
unaffected quality factor. Our devices are fully waveguide-coupled and
represent a promising platform for on-chip van der Waals photonics.

15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: eess
6
The categories of this paper are: astro-ph
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The categories of this paper are: stat
30
The categories of this paper are: q-alg