Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Femtosecond-laser-induced nanoscale blisters in polyimide thin films
  through nonlinear absorption   Nonlinear absorption of femtosecond laser pulses provides a unique
opportunity to confine energy deposition in any medium to a region that is
below the focal diameter of a pulse. Illumination of a polymer film through a
transparent high bandgap material such as glass, followed by nonlinear
absorption of 800 nm light in polymers, allows us to further restrict
absorption to a very thin layer along the propagation direction. We demonstrate
this confinement by simulating femtosecond-laser-induced polymer modification
by linear, two-photon and three-photon absorption, and discuss the control over
energy absorption in polymers that multiphoton processes offer. Energy
deposited behind a thin polymer film induces a protruding blister. We present
experimental results of blister diameter and height scaling with pulse energy.
Using 0.95 NA focussing, we obtained laser-induced blisters with diameters as
small as 700 nm suggesting blister-based Laser-Induced Forward Transfer is
possible on and below the single-micron scale. Sub-micrometer blister formation
using femtosecond lasers also offers a novel method of direct, precise
laser-writing of microstructures on films with single laser pulses. This method
is a possible alternative to lithography, laser milling, and laser-based
additive machining which leaves the surface composition unchanged.

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The categories of this paper are: math
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: solv-int
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: chem-ph