Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear guiding of light in tunable food-dye solutions   We provide the first demonstration of nonlinear self-trapping of light in
solutions of food coloring dyes, leading to dirt cheap soliton waveguides. The
optical self-focusing nonlinearity observed in such solutions is attributed to
the optical absorption force acting on dye molecules, as the thermal effect at
relatively higher power results in a self-defocusing nonlinearity. We found the
nonlinear response increases when the laser wavelength is switched to near the
peak absorption for all food dyes tested. Furthermore, the absorption-dependent
nonlinearity can be tuned by making purposive samples of different food dyes.
In particular, with appropriately mixing of dye solutions, nonlinear response
arises for otherwise inactive wavelengths, leading to interaction between two
beams of different wavelengths and formation of a coupled soliton-like pair. At
milliwatt low power levels, self-trapping achieved at one wavelength in
food-dye solutions can serve as low-cost waveguides for optical beams at other
wavelengths.

22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
2
The categories of this paper are: math