Re: MPB basic on non zero kz values

"[email protected]" <[email protected]> Thu, 12 Mar 2015 15:03:18 +0000
Newsgroups gmane.comp.science.photonic-bands
Message-ID <[email protected]>
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Hello Subir Majumder,


your idea about "(...) for a non zero kz value, there will be no TE or TM p=
olarization." is wrong. I will try to clarify the things for you:


The kz component represents a wavevector, with magnitude n_eff*k and direct=
ion equal to the wave propagation direction, where n_eff is the effective r=
efractive index, and k is the wave number.

That being said the wavevector kz is well defined in the longitudinal direc=
tion of the fiber (although the wavevector k is allowed to have other non-n=
ull components). In agreement to that, all the fundamental propagation mode=
s can be described by two types of polarization: the transverse electric (T=
E) modes, where the electric-field is confined to the xy plane (i.e. the tr=
ansverse direction), and the transverse magnetic (TM) modes, where the magn=
etic field is confined to the xy plane.


Thus, you can conclude that for non-zero kz, you expect non-zero TE or TM p=
olarizations. And, in fact, with MPB, you can compute TE and TM photonic ba=
nds. You can compute the TE and TM bands separately, or the full bands (the=
 full bands for fundamental modes are a superposition of TE and TM bands). =
The MPB for doing that are:


(run-te)        ; run for TE bands;
(run-tm)        ; rum for TM bands;
(run)           ; run for TE and TM the bands.

I hope this helps you in the studying of the coupling of the fields.


S=EDlvia M.G. Rodrigues



________________________________
From: Subir Majumder <[email protected]>
Sent: Friday, February 13, 2015 12:14 PM
To: [email protected]
Cc: [email protected]
Subject: Re: [MPB-discuss] MPB basic on non zero kz values

Thanks Sir for your reply.
This is solved.

Now, what I'm facing that for a non zero kz value, there will be no TE or T=
M polarization. The fields for a particular band at a certain point should =
be coupled. is there any way in mpb to map that coupled field? (I tried tha=
t but the results seem to be not reliable)

(eg. if for an inplane condition, if we search for e field distribution for=
 a band (say band 2) at a point (say K point) of a a hexagonal PC, mpb retu=
rns e field distribution)

Thanks

Subir

Subir Majumder



On Thu, Feb 12, 2015 at 11:30 PM, [email protected]<mailto:[email protected]> <=
[email protected]<mailto:[email protected]>> wrote:
Hello,

if you need to put non-zero values for kz in MPB, for instance in an hexago=
nal lattice, it can be done like this:

(set! k-points (list (vector3 0 0 kz_mpb)              ; gamma
                     (vector3 0 0.5 kz_mpb)            ; m
                     (vector3 (/ -3) (/ 3) kz_mpb)     ; k
                     (vector3 0 0 kz_mpb)))            ; gamma

where, kz_mpb in fact is unitless, it is:
kz_mpb =3D kz.a/(2pi),
where kz can be measured in [m^-1], and a is the lattice periodicity in [m]=
.

S=EDlvia M.G. Rodrigues


________________________________________
From: mpb-discuss <[email protected]<mailto:mpb-discuss=
[email protected]>> on behalf of Subir <[email protected]=
m<mailto:[email protected]>>
Sent: Friday, December 26, 2014 10:18 AM
To: [email protected]<mailto:[email protected]>
Subject: [MPB-discuss] MPB basic on non zero kz values

Sir, I'm a new user of MPB. I work on photonic crystal fibers. My simple
question is what is the unit of kz values used in the package if need to pu=
t
non zero values of kz.


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<head>
<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Diso-8859-=
1">
<style type=3D"text/css" style=3D"display:none;"><!-- P {margin-top:0;margi=
n-bottom:0;} --></style>
</head>
<body dir=3D"ltr">
<div id=3D"divtagdefaultwrapper" style=3D"font-size:12pt; color:#000000; ba=
ckground-color:#FFFFFF; font-family:Calibri,Arial,Helvetica,sans-serif">
<p style=3D"margin-top: 0px; margin-bottom: 0px;">Hello Subir Majumder,<br>
</p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><br>
</p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;">your idea about &quot;(..=
.) for a non zero kz value, there will be no TE or TM polarization.&quot; i=
s wrong. I will try to clarify the things for you:<br>
<br>
</p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;">The kz component represen=
ts a wavevector,&nbsp;with&nbsp;magnitude n_eff*k&nbsp;and direction equal =
to the wave propagation direction, where n_eff is the effective refractive =
index, and k is the wave number.<br>
</p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;">That being said the wavev=
ector kz&nbsp;is well&nbsp;defined in the&nbsp;longitudinal direction of th=
e fiber (although the wavevector k is allowed to have other non-null compon=
ents). In agreement to that, all the fundamental&nbsp;propagation
 modes can be described by&nbsp;two <span style=3D"font-size:12pt">types of=
 polarization: the transverse electric (TE) modes, where the electric-field=
 is confined to the xy plane (i.e. the transverse direction), and the trans=
verse magnetic (TM) modes, where the magnetic
 field is confined to the xy plane.</span></p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><span style=3D"font-size:=
12pt"><br>
</span></p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><span style=3D"font-size:=
12pt">Thus, you can conclude that for non-zero kz, you&nbsp;expect non-zero=
 TE or TM&nbsp;</span>polarizations<span style=3D"font-size:12pt">. And, in=
 fact, with&nbsp;MPB, you can compute TE and TM photonic
 bands. You can compute the TE and TM bands&nbsp;</span>separately<span sty=
le=3D"font-size:12pt">, or the full bands (the full bands for fundamental m=
odes&nbsp;are a superposition of TE and TM bands). The MPB for doing that&n=
bsp;are:</span></p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><span style=3D"font-size:=
12pt"><br>
</span></p>
<div><span style=3D"font-size:12pt">(run-te) &nbsp; &nbsp; &nbsp; &nbsp;</s=
pan><span style=3D"font-size:12pt">; run for TE bands;</span><br>
</div>
<div>
<div style=3D"font-family:Calibri,Arial,Helvetica,sans-serif; font-size:16.=
3636360168457px">
(run-tm) &nbsp; &nbsp; &nbsp; &nbsp;;&nbsp;rum for TM bands;<br>
</div>
<span style=3D"font-size:12pt">(run) &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbs=
p;; run for TE and TM the bands.</span><br>
</div>
<div><br>
I hope this helps you in the studying of&nbsp;the coupling of the fields.<b=
r>
</div>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><br>
<span style=3D"font-size:12pt"></span></p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><span style=3D"font-size:=
12pt">S=EDlvia M.G. Rodrigues<br>
</span></p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><br>
</p>
<p style=3D"margin-top: 0px; margin-bottom: 0px;"><br>
</p>
<div style=3D"color:rgb(33,33,33)">
<hr tabindex=3D"-1" style=3D"display:inline-block; width:98%">
<div id=3D"divRplyFwdMsg" dir=3D"ltr"><font style=3D"font-size:11pt" color=
=3D"#000000" face=3D"Calibri, sans-serif"><b>From:</b> Subir Majumder &lt;s=
[email protected]&gt;<br>
<b>Sent:</b> Friday, February 13, 2015 12:14 PM<br>
<b>To:</b> [email protected]<br>
<b>Cc:</b> [email protected]<br>
<b>Subject:</b> Re: [MPB-discuss] MPB basic on non zero kz values</font>
<div>&nbsp;</div>
</div>
<div>
<div dir=3D"ltr">Thanks Sir for your reply.
<div>This is solved.<br>
<br>
Now, what I'm facing that for a non zero kz value, there will be no TE or T=
M polarization. The fields for a particular band at a certain point should =
be coupled. is there any way in mpb to map that coupled field? (I tried tha=
t but the results seem to be not
 reliable)</div>
<div><br>
</div>
<div>(eg. if for an inplane condition, if we search for e field distributio=
n for a band (say band 2) at a point (say K point) of a a hexagonal PC, mpb=
 returns e field distribution)</div>
<div><br>
</div>
<div>Thanks</div>
<div><br>
</div>
<div>Subir</div>
<div class=3D"gmail_extra"><br clear=3D"all">
<div>
<div class=3D"gmail_signature">
<div dir=3D"ltr">
<div>
<div dir=3D"ltr">
<div>
<div dir=3D"ltr">Subir Majumder</div>
<div dir=3D"ltr"><br>
</div>
<div dir=3D"ltr"><br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
<div class=3D"gmail_quote">On Thu, Feb 12, 2015 at 11:30 PM, <a href=3D"mai=
lto:[email protected]">
[email protected]</a> <span dir=3D"ltr">&lt;<a href=3D"mailto:[email protected]=
" target=3D"_blank">[email protected]</a>&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex; border-left:1=
px #ccc solid; padding-left:1ex">
Hello,<br>
<br>
if you need to put non-zero values for kz in MPB, for instance in an hexago=
nal lattice, it can be done like this:<br>
<br>
(set! k-points (list (vector3 0 0 kz_mpb)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;=
 &nbsp; &nbsp; ; gamma<br>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp=
;(vector3 0 0.5 kz_mpb)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ; m<br>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp=
;(vector3 (/ -3) (/ 3) kz_mpb)&nbsp; &nbsp; &nbsp;; k<br>
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp=
;(vector3 0 0 kz_mpb)))&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ; gamma<br=
>
<br>
where, kz_mpb in fact is unitless, it is:<br>
kz_mpb =3D kz.a/(2pi),<br>
where kz can be measured in [m^-1], and a is the lattice periodicity in [m]=
.<br>
<br>
S=EDlvia M.G. Rodrigues<br>
<br>
<br>
________________________________________<br>
From: mpb-discuss &lt;<a href=3D"mailto:[email protected]=
du">[email protected]</a>&gt; on behalf of Subir &lt;<a=
 href=3D"mailto:[email protected]">[email protected]</a=
>&gt;<br>
Sent: Friday, December 26, 2014 10:18 AM<br>
To: <a href=3D"mailto:[email protected]">mpb-discuss@ab-initio.=
mit.edu</a><br>
Subject: [MPB-discuss] MPB basic on non zero kz values<br>
<br>
Sir, I'm a new user of MPB. I work on photonic crystal fibers. My simple<br=
>
question is what is the unit of kz values used in the package if need to pu=
t<br>
non zero values of kz.<br>
<br>
<br>
_______________________________________________<br>
mpb-discuss mailing list<br>
<a href=3D"mailto:[email protected]">[email protected].=
edu</a><br>
<a href=3D"http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-discuss" t=
arget=3D"_blank">http://ab-initio.mit.edu/cgi-bin/mailman/listinfo/mpb-disc=
uss</a></blockquote>
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<br>
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