Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multicolour wavelength-tunable lasing from a single bandgap-graded alloy
  nanoribbon   Tunable lasing from 578 nm to 640 nm is observed from a single CdSSe
bandgap-graded alloy nanoribbon, by selecting the excited spot at room
temperature. Though reabsorption is a serious problem to achieve lasing at
short wavelength, multiple scatters on the nanoribbon form localized cavities,
and thus realize lasing at different wavelengths. By increasing the excitation
area, we also observe multicolour lasing from the same nanoribbon
simultaneously.

18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat