Re: About the lightcone and projected slab mode

The easiest way to project the slab modes for a line defect is just to use 
a large supercell with no defect.

On Thu, 15 Nov 2007, Ryan Hao wrote:
> Dear Prof.Steven and others,
>      Thank you for your answer.
>      But my question is how to set the K path in calculating and
> projecting the slab mode?
>      You known, projecting the slab mode needs to scan the full area
> of Brillouin zone, then project to the waveguide direction.
>
>
> Below is my code, Could you please have a look and tell me whether it
> is correct or not (I think there may something wrong in setting the
> reciprocal lattice and k path ):
> (define-param kymin 0)
> (define-param kymax 0.57735)
> (define-param k-interp 20)
> (define (do-stuff k k-hi k-inc)
> (if (<= k k-hi)
>      (begin
>
>  (set! k-points (interpolate k-interp (list (lattice->reciprocal
> (vector3 k kymin 0))
>          (lattice->reciprocal (vector3 k kymax 0)))))
> 	(run-zeven )
>  (do-stuff (+ k k-inc) k-hi k-inc)
>  )))
> (do-stuff 0 0.5 0.1)
>
>
> Best wishes
> Ryan
>
>
> On Mar 28, 2007 2:20 AM, Steven G. Johnson <[email protected]> wrote:
>> On Tue, 13 Mar 2007, Ryan Hao wrote:
>>> In the case of line defect waveguide in photonic crystal slab,I succeed
>>> in caculating the waveguide mode with MPB.but there still something
>>> left:I must find way to project the band strucure of the regular lattice
>>> of the slab(slab mode) and the lightcone?You can see in the below
>>> picture,the blue line represent for the lightcone,and the green line
>>> represent for slab mode.
>>
>> Projecting the light cone (for a uniform substrate/superstrate) is easy --
>> it is just the kmag output column divided by the substrate index.
>>
>> For projecting the modes of the unperturbed slab, the easiest thing to do
>> is to use the same computational cell as your line-defect waveguide, but
>> without the defect.  (In fact, you can use a smaller supercell if you
>> want, as long as you plot the slab bands for several values of ky from 0
>> to 0.5, where y is the direction perpendicular to your waveguide, assuming
>> a rectilinear supercell.)
>>
>> Cordially,
>> Steven G. Johnson
>>
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>>
>
>
>
> -- 
> ===========================================
>
> Best wishes
>
>                      Yours,
>                      Ryan Hao
>
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