Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nanoscale Thermotropic Phase Transitions Enhance Photothermal Microscopy
  Signals   The photothermal heterodyne imaging technique enabled studies of individual
weakly absorbing nano-objects in various environments. It uses a photo-induced
change in the refractive index of the environment. Taking advantage of the
dramatic index of refraction change occurring around a thermotropic liquid
crystalline phase transition, we demonstrate a 40-fold signal-to-noise ratio
enhancement for gold nanoparticles imaged in 4-Cyano-4'-pentylbiphenyl (5CB)
liquid crystals over those in a water environment. We studied the photothermal
signal as a function of probe laser polarization, heating power, and sample
temperature quantifying the optimal enhancement. This study established
photothermal microscopy as a valuable technique for inducing and/or detecting
local phase transitions at the nanometer scales.

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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: patt-sol
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: chem-ph
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The categories of this paper are: supr-con