Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Feedback-assisted Femtosecond Pulsed Laser Ablation of Non-Planar Metal
  Surfaces: Fabrication of Optical Apertures on Tapered Fibers for Optical
  Neural Interfaces   We propose a feedback-assisted direct laser writing method to perform laser
ablation of fiber optics devices in which their light-collection signal is used
to optimize their properties. A femtosecond-pulsed laser beam is used to ablate
a metal coating deposited around a tapered optical fiber, employed to show the
suitability of the approach to pattern devices with small radius of curvature.
During processing, the same pulses generate two-photon fluorescence in the
surrounding environment and the signal is monitored to identify different
patterning regimes over time through spectral analysis. The employed fs beam
mostly interacts with the metal coating, leaving almost intact the underlying
silica and enabling fluorescence to couple with a specific subset of guided
modes, as verified by far-field analysis. Although the method is described here
for tapered optical fibers used to obtain efficient light collection in the
field of optical neural interfaces, it can be easily extended to other
waveguides-based devices and represents a general approach to support the
implementation closed-loop laser ablation system of fiber optics.

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The categories of this paper are: chem-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat