Imaginary part of SHG calculation

Questions and doubts about features of non linear optic in Yambo (yamb_nl)

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pangrt
Posts: 25
Joined: Thu Jun 18, 2020 1:38 pm

Imaginary part of SHG calculation

Post by pangrt » Sat Nov 28, 2020 6:17 am

Dear developers,
I am running SHG with Yambo and got the SHG chi, and how could I obtain the imaginary part of the dielectric constant at both
ω/2 and ω? (As in attached, the red solid and dashed lines)



Thanks!

Rongtian
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RongTianPang, Inner Mongolia University, Hohhot, China :)

lyzhao
Posts: 36
Joined: Tue May 31, 2016 8:02 am

Re: Imaginary part of SHG calculation

Post by lyzhao » Sat Nov 28, 2020 8:25 am

Do you mean the imaginary part of the dielectric constant or SHG?
The dielectric constant is linear optical paramater and not SHG.
Youzhao Lan
College of Chemistry and Materials Science,
Zhejiang Normal University,
Jinhua, Zhejiang, China.
HomePage: http://blog.sciencenet.cn/u/lyzhao

pangrt
Posts: 25
Joined: Thu Jun 18, 2020 1:38 pm

Re: Imaginary part of SHG calculation

Post by pangrt » Sat Nov 28, 2020 11:32 am

Dear Zhao,
I think it is the imaginary part of the dielectric. How to obtain the dielectric constant at ω/2?

Thanks!

Rongtian
RongTianPang, Inner Mongolia University, Hohhot, China :)

lyzhao
Posts: 36
Joined: Tue May 31, 2016 8:02 am

Re: Imaginary part of SHG calculation

Post by lyzhao » Sat Nov 28, 2020 11:41 am

please see the first tutorial at http://www.attaccalite.com/lumen/tutorials.html.
Youzhao Lan
College of Chemistry and Materials Science,
Zhejiang Normal University,
Jinhua, Zhejiang, China.
HomePage: http://blog.sciencenet.cn/u/lyzhao

pangrt
Posts: 25
Joined: Thu Jun 18, 2020 1:38 pm

Re: Imaginary part of SHG calculation

Post by pangrt » Sat Nov 28, 2020 12:14 pm

I notice that just an abs. of ω instead of ω/2?

Thanks!
Rongtian
RongTianPang, Inner Mongolia University, Hohhot, China :)

AmberLee123
Posts: 34
Joined: Sun Jul 26, 2020 7:00 am
Location: Xiamen, Fujian, China

Re: Imaginary part of SHG calculation

Post by AmberLee123 » Thu Feb 17, 2022 9:27 am

I think the abs. of ω/2 is just to extend the abs. of ω in the picture, ie. f(x/2) compared with f(x).
So there is no specially abs. of ω/2 in the output file from yambo. We just read abs. ω and then recalculate it.

Best.
Dr. Guoyu Yang
School of Science, Jimei University, Xiamen, Fujian, China

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claudio
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Re: Imaginary part of SHG calculation

Post by claudio » Thu Feb 17, 2022 2:49 pm

Dear Rongtian

once you have the imaginary part of the dielectric constant, just plot it with the argument divided by two
for example in python:


plt.plot(EPS[:,0]/2., EPS[:,1],color="red", linewidth=3.0, linestyle="-", label="$\epsilon_2(\omega/2)$")
plt.plot(EPS[:,0], EPS[:,1],color="red", linewidth=3.0, linestyle="--",label="$\epsilon_2(\omega)$")

best
Claudio
Claudio Attaccalite
[CNRS/ Aix-Marseille Université/ CINaM laborarory / TSN department
Campus de Luminy – Case 913
13288 MARSEILLE Cedex 09
web site: http://www.attaccalite.com

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