Dear Mr. Philipp,
You missed one point in scaling property. While one corresponds to length
(radius/lattice spacing), the other corresponds to the dielectric contrast.
When you changed the dielectric constant from 11.4 to 2.45, obviously, the
dielectric contrast got changed and that is the reason why you couldn't observe
any band gap (I assumed that you took the dielectric constant of background as
1). You can take the background epsilon in the first case in such a way that
the contrast is equal to that in second case and you will get the same result.
regards,
Nagesh.
Note: forwarded message attached.
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Dear all,
I'm wondering about an easy triangular lattice of holes-calculation. I
simulated that lattice with radius/lattice constant=0.45 once with
epsilon=11.4 (like e.g. in the book of Joannopoulos) and once with
epsilon=2.45. There appeared a bandgap in tm-polarization between band 2 and
3 with the bigger epsilon, but none with the smaller value. But shouldn't it
look the same (due to the scaling properties of the master equations)?
Or is it only a resolution/mesh-size-problem?
Thanks for your help
Philipp
Above is my ctl-file:
(set! geometry-lattice (make lattice (size 1 1 no-size)
(basis1 (/ (sqrt 3) 2) 0.5)
(basis2 (/ (sqrt 3) 2) -0.5)))
(set! default-material (make dielectric (epsilon 2.45)))
(set! geometry
(list
(make cylinder
(material (make dielectric (epsilon 1)))
(center 0 0 0) (radius 0.45) (height infinity))))
(set! k-points (list (vector3 0 0 0)
(vector3 0 0.5 0)
(vector3 (/ -3) (/ 3) 0)
(vector3 0 0 0)))
(set! k-points (interpolate 128 k-points))
(set! resolution 64)
(set! num-bands 12)
(set! mesh-size 10)
(run-tm)
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