Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Efficient Third Harmonic Generation in Composite Aluminum Nitride /
  Silicon Nitride Microrings   Aluminum nitride and silicon nitride have recently emerged as important
nonlinear optical materials in integrated photonics respectively for their
quadratic and cubic optical nonlinearity. A composite aluminum nitride and
silicon nitride waveguide structure, if realized, will simultaneously allow
highly efficient second and third harmonic generation on the same chip platform
and therefore assists 2f-3f self-referenced frequency combs. On-chip third
harmonic generation, being a higher order nonlinear optics effect, is more
demanding than second harmonic generation due to the large frequency difference
between the fundamental and third harmonic frequencies which implies large
change of refractive indices and more strigent requirements on phase matching.
In this work we demonstrate high-efficiency third harmonic generation in a high
Q composite aluminum nitride / silicon nitide ring cavity. By carefully
engineering the microring resonator geometry of the bilayer structure to
optimize the quality factor, mode volume and modal overlap of the optical
fields, we report a maximum conversion efficiency of $180\%\,\mathrm{W^{-2}}$.
This composite photonic chip design provides a solution for efficient frequency
conversion over a large wavelength span, broadband comb generation and
self-referenced frequency combs.

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The categories of this paper are: funct-an
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph