I go through these three pages and revise my ctl. The control file and results
are as follows,
-------------------------------------------------------------------------------------------------
(define-param eps 13) ; dielectric constant of waveguide
(define-param w 1.2) ; width of waveguide
(define-param r 0.36) ; radius of holes
; The cell dimensions
(define-param sy 12) ; size of cell in y direction (perpendicular to wvg.)
(define-param dpml 1) ; PML thickness (y direction only!)
(set! geometry-lattice (make lattice (size 1 sy no-size)))
(set! geometry
(list (make block (center 0 0) (size infinity w infinity)
(material (make dielectric (epsilon eps))))
(make cylinder (center 0 0) (radius r) (height infinity) (material
air))
))
(set! pml-layers (list (make pml (direction Y) (thickness dpml))))
(set-param! resolution 40)
(define-param fcen 0.1893) ; pulse center frequency
(define-param df 0.01) ; pulse freq. width: large df = short impulse
(set! sources (list
(make source
(src (make gaussian-src (frequency fcen) (fwidth df)))
(component Hz) (center 0.1234 0))))
(set! symmetries (list (make mirror-sym (direction Y) (phase -1))))
(define-param kx false) ; if true, do run at specified kx and get fields
(define-param k-interp 19) ; # k-points to interpolate, otherwise
(use-output-directory)
(define-param T 300)
(if kx
(begin
(set! k-point (vector3 kx))
(run-sources+
T (at-beginning output-epsilon)
(after-sources (harminv Hz (vector3 0.1234 0) fcen df)))
(run-until (/ 1 fcen) (at-every (/ 1 fcen 20) output-hfield-z)))
(run-k-points 300 (interpolate k-interp (list (vector3 0) (vector3 0.5)))))
------------------------------------------------------------------------------------------------------------
$ meep T=300 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
harminv0:, 0.189320215443941, 8.62283713653739e-13, -109778378302.971,
187.767980786154, 101.674511877595-157.857873553911i, 1.73021160676177e-13
$ meep T=1000 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
harminv0:, 0.189320215446347, 2.47659191200206e-12, -38221923953.0065,
187.767979563821, 101.674516474146-157.857869139388i, 4.59078637768214e-12
$ meep T=3000 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
harminv0:, 0.189320216242936, 2.56399298663662e-8, -3691901.99095048,
187.722613765333, 101.651135012216-157.818967394976i, 1.14895688004523e-8
$ meep T=3000 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
MEEP gives no results.
$ meep resolution=20 T=300 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
harminv0:, 0.189316377325154, -1.64875713950528e-10, 574118445.916053,
187.668563180414, 104.657993268057-155.776102311312i, 7.42473505662106e-10
$ meep resolution=20 T=1000 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
harminv0:, 0.189316317177088, -1.68688252136474e-8, 5611425.65588755,
187.678472061645, 104.634070264008-155.804108467589i, 6.24142280764796e-8
$ meep resolution=20 T=3000 kx=0.4 holey-wvg-bands.ctl
harminv0:, frequency, imag. freq., Q, |amp|, amplitude, error
MEEP gives no results.
As we can see, when resolution is 40, the Q is always negative. But when
resolution is 20, the Q is positive. What's wrong? and why MEEP gives no
results when T is too big?
(I use a narraw Gaussian beam(df=0.01;when df=0.001,MEEP gives no results), a
high resolution and wait a long time.)
Mario
----- Original Message ----
From: matt <[EMAIL PROTECTED]>
To: Andrew Andrew <[EMAIL PROTECTED]>
Cc: Alejandro Rodriguez <[EMAIL PROTECTED]>; meep-discuss@ab-initio.mit.edu
Sent: Sunday, April 22, 2007 8:23:11 PM
Subject: Re: [Meep-discuss] why Q is negative?
This topic has been discussed on the list before:
http://article.gmane.org/gmane.comp.science.electromagnetism.meep.general/166/
http://article.gmane.org/gmane.comp.science.electromagnetism.meep.general/603/
http://article.gmane.org/gmane.comp.science.electromagnetism.meep.general/601/
Best,
Matt
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