Dear Prof Steven and MPB users,
I am new user for MPB software, and doing Photonic crystal slab waveguide
simulation.
I am trying to reproduce Fig.2b in this paper "Wider bandwidth with high
transmission through waveguide bends in two dimensional photonic crystal
slabs, Applied Physics Letters, 2002"
By setting
----
(set! geometry-lattice (make lattice
(basis1 1 0)
(basis2 0 (/ (sqrt 3) 2))
(size (* 2 b) supercell-y no-size)))
;
(define Gamma (vector3 0 0 0))
(define K' (lattice->reciprocal (vector3 0.3 0 0)))
(set! k-points (interpolate 20 (list Gamma K')))
----
I able to reproduce the same graph for supercell at BEND region. However, I
am not sure why I have to plot the X-axis by the values listed in Kmag/2pi
column (why not by the k1 colum?).
Here are some of the values obtained from grep command:
k1=0, 0.0989743, 0.173205, 0.272179, 0.34641, 0.445384, 0.519615 ;
k2=0, 0, 0, 0, 0, 0, 0 ;
k3=0, 0, 0, 0, 0, 0, 0 ;
Kmag/2pi=0, 0.057413, 0.1, 0.157143, 0.2, 0.257143, 0.3;
For normal straight waveguide supercell band diagram, the X-axis is wave
vector(2pi/a) from 0 to 0.5, and the value for k1 is the same as kmag/2pi.
however, in bend region, the k1 is not the same as kmag/2pi as shown above.
Can you explain some reasons for me to understand it?
For the case of 3D PWE simulation, I only changed the 'size' from 'no-size'
to 'supercell-h', where supercell-h is a value to represent the finite
thickness of the PhC. (assume the substrate and superstrate are air)
To plot the light line, I just need to plot kmag/2pi vs Kmag/2pi for both X
and Y axes?
If so, my light line for Bend region is plotted until wavevector=0.3 only,
but, light line for Straight Waveguide (3D case)is plotted until
wavevector=0.5. Is it possible to match the wavevectors in this situation to
achieve high output transmission?
One more question about the folding, how can I know how many times the band
is folded from the band diagram or from the output field plot for the modes
in band diagram?
i hope you can guide me to solve my problems.
Thank You
Regards,
DC
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