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Integrate extra dimension

Posted Mar 6, 2017, 7:12 a.m. EST Results & Visualization Version 5.2 8 Replies

Yuanlong Fan
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Hi, All,

I am modelling an LED using comsol and currently facing a problem of integrating an extra dimension variable over the base geometry which is a 2D square. The extra dimension variable is obtained from the Optical Transitions in the Semiconductor Physics. The variable's name is the emitted power per unit volume and energy (1/(m^3*s)) (semi.ot1.dP_dE) from which I would like to calculate the LED emitted power over a boundary of the based geometry.
Currently, I can only obtain the "semi.ot1.dP_dE" for a specific point on the boundary using the following command:

"comp1.atxd2(5e-6, 10e-6, semi.ot1.dP_dE)"

where 5e-6 and 10e-6 are the x and y coordinate.

Anyone can help how to intergrate "semi.ot1.dP_dE" over a boundary?

Many thanks!
8 Replies Last Post Sep 1, 2017, 1:59 p.m. EDT
Gunnar Andersson COMSOL Employee

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Posted: 7 years ago Mar 6, 2017, 9:47 a.m. EST
Anyone can help how to intergrate "semi.ot1.dP_dE" over a boundary?


Without seeing your model I don't know for sure, but I would create a Results > Derived Values > Surface Integration and use the expression comp1.atxd2(x, y, semi.ot1.dP_dE). If this doesn't work I suggest that you send the model to COMSOL support.
[QUOTE]Anyone can help how to intergrate "semi.ot1.dP_dE" over a boundary?[/QUOTE] Without seeing your model I don't know for sure, but I would create a Results > Derived Values > Surface Integration and use the expression comp1.atxd2(x, y, semi.ot1.dP_dE). If this doesn't work I suggest that you send the model to COMSOL support.
Yuanlong Fan
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Posted: 7 years ago Mar 6, 2017, 10:14 a.m. EST
Hi, Gunnar,

Thank you for your prompt reply. I have tried your suggestion but it was not working. Sorry that the model is too big to attach here and I will try to contact COMSOL support.

Cheers!
Hi, Gunnar, Thank you for your prompt reply. I have tried your suggestion but it was not working. Sorry that the model is too big to attach here and I will try to contact COMSOL support. Cheers!
Gunnar Andersson COMSOL Employee

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Posted: 7 years ago Mar 6, 2017, 10:36 a.m. EST
Reading your example again I realize that I probably misunderstood the model. Does it have one or two extra dimensions? The first two arguments to the atxd2 operator are coordinates in the extra dimension, so my suggestion to use x and y for these arguments was wrong.
Reading your example again I realize that I probably misunderstood the model. Does it have one or two extra dimensions? The first two arguments to the atxd2 operator are coordinates in the extra dimension, so my suggestion to use x and y for these arguments was wrong.
Daniel Smith COMSOL Employee

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Posted: 7 years ago Mar 6, 2017, 10:48 a.m. EST
Hi, the variable semi.ot1.dP_dE exists in the product space formed by the base geometry and extra dimension. Therefore, to integrate the expression over the base geometry, you first need to integrate it over the extra dimension. Therefore, you need to use the built in integration operator which can integrate over the extra dimension. In this case: semi.ot1.xdintopall(...). This can be seen in the Equation View for the Optical Transitions feature.

So, you should be able to perform a surface integral on the base geometry under Derived Values (as suggested by Gunnar) using the expression:
semi.ot1.xdintopall(semi.ot1.dP_dE)

This way, the expression semi.ot1.dP_dE is integrated over both the base geometry and the extra dimension.

Dan
Hi, the variable semi.ot1.dP_dE exists in the product space formed by the base geometry and extra dimension. Therefore, to integrate the expression over the base geometry, you first need to integrate it over the extra dimension. Therefore, you need to use the built in integration operator which can integrate over the extra dimension. In this case: semi.ot1.xdintopall(...). This can be seen in the Equation View for the Optical Transitions feature. So, you should be able to perform a surface integral on the base geometry under Derived Values (as suggested by Gunnar) using the expression: semi.ot1.xdintopall(semi.ot1.dP_dE) This way, the expression semi.ot1.dP_dE is integrated over both the base geometry and the extra dimension. Dan
Yuanlong Fan
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Posted: 7 years ago Mar 6, 2017, 10:55 a.m. EST


This way, the expression semi.ot1.dP_dE is integrated over both the base geometry and the extra dimension.

Dan


Hi, Dan,

Thank you very much for your help! The problem is solved.

Best regards

Yuanlong

[QUOTE] This way, the expression semi.ot1.dP_dE is integrated over both the base geometry and the extra dimension. Dan [/QUOTE] Hi, Dan, Thank you very much for your help! The problem is solved. Best regards Yuanlong
Yuanlong Fan
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Posted: 7 years ago Mar 6, 2017, 10:56 a.m. EST
Hi, Gunnar,

Thank you very much for your help! The problem is solved.

Best regards

Yuanlong
Hi, Gunnar, Thank you very much for your help! The problem is solved. Best regards Yuanlong
Chen Gong
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Posted: 7 years ago Sep 1, 2017, 12:22 a.m. EDT
Howdy,

The topic in this discussion is attractive for me. I have a very similar question recently:
I have built a 1D MQW LED model.
And I use the following expressions to generate the spectrum plot:
y-axis: comp1.atxd1(0.107e-6, semi.ot1.dP_dE)
x_axis: hbar_const*comp1.atxd1(0.107e-6, semi.ot1.omega)/e_const
So, I got the spectrum generated by the point: 0.107e-6; and the result matches my expectation.
But now I want to see the spectrum of the whole 1D model instead of just one point. Can you help me with the expressions?

Thanks a lot!
Howdy, The topic in this discussion is attractive for me. I have a very similar question recently: I have built a 1D MQW LED model. And I use the following expressions to generate the spectrum plot: y-axis: comp1.atxd1(0.107e-6, semi.ot1.dP_dE) x_axis: hbar_const*comp1.atxd1(0.107e-6, semi.ot1.omega)/e_const So, I got the spectrum generated by the point: 0.107e-6; and the result matches my expectation. But now I want to see the spectrum of the whole 1D model instead of just one point. Can you help me with the expressions? Thanks a lot!
Daniel Smith COMSOL Employee

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Posted: 7 years ago Sep 1, 2017, 1:59 p.m. EDT
Hi Chen, the only way to do this with a 1D plot would be to create an animation.
* Go to Results>Parameters and add a new parameter, call it ds with value 0.107e-6
* In your plot, change the expressions to:
y-axis: comp1.atxd1(ds, semi.ot1.dP_dE)
x_axis: hbar_const*comp1.atxd1(ds, semi.ot1.omega)/e_const
Then do Export>Animation>Player and set the Subject to the plot group above.
* Set the Sequence type to Result parameter and for the Parameter choose ds.
* Set the Start and Stop values to be the limits of the geometry. In the COMSOL Application Library example, this is 0.15e-6 to 0.155e-6.
* Click the Play button. This will animate the spectrum as you sweep through the geometry.

Hi Chen, the only way to do this with a 1D plot would be to create an animation. * Go to Results>Parameters and add a new parameter, call it ds with value 0.107e-6 * In your plot, change the expressions to: y-axis: comp1.atxd1(ds, semi.ot1.dP_dE) x_axis: hbar_const*comp1.atxd1(ds, semi.ot1.omega)/e_const Then do Export>Animation>Player and set the Subject to the plot group above. * Set the Sequence type to Result parameter and for the Parameter choose ds. * Set the Start and Stop values to be the limits of the geometry. In the COMSOL Application Library example, this is 0.15e-6 to 0.155e-6. * Click the Play button. This will animate the spectrum as you sweep through the geometry.

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