Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photonic flame effect   We observed new effect which we called photonic flame effect (PFE). Several
3-dimensional photonic crystals (artificial opals) were posed on Cu plate at
the temperature of liquid nitrogen (77K). Typical distance between them was 1-5
centimeters. Long-continued optical luminescence was excited in one of them by
the ruby laser pulse. Analogous visible luminescence manifesting time delay
appeared in other samples of the crystals. Experiments were realized for opal
crystals and for nanocomposites (opals filled with nonlinear liquids).

19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg