lattice constant in optiFDTD

[Poonam Jindal]

i wanted to know, how to define the lattice constant a in optiFDTD.

[Scott Newman]

Hi Poonam,

The lattice constant is the Scale parameter within Lattice Dimensions within the Crystal Lattice properties. I would encourage you to review the tutorials (located within the manuals that are installed with the product) and webinars (https://www.gotostage.com/channel/optiwave) as there are a number of points were we review creation of photonic crystals in the product.

Scott

[Poonam Jindal]

Hi Scott

Thank you so much.. i will definitely go through the webinars.

[Poonam Jindal]

Hi
I have tried to define the lattice constant under crystal properties- lattice dimensions
but when I click ok, the pop up window says unknown variable. Then I tried to define the variable under variables and functions. I assigned the variable name – lattice constant, expression -a but unable to assign value to it.

I wanted to know where am i doing it wrong?
the snapshots are also attached for reference.

Attachments:

1. lattice-constant.docx

[Scott Newman]

Hi Poonam,

It is how you are defining your user variable. The way this form is configured is to support the use of expressions with other variables if you wanted. You put the expression/value you want in the expression box and the value box is the value your expression evaluates to. So let us assume you want a lattice constant of 0.4 um then for your case

Name: a
Expression: 0.4
Value: 0.4 (This is generated by the product)

To explain what I mean if you had a variable b that was 0.3 and you wanted your lattice constant to be 2 times that then you would do this

Name: a
Expression: 2*b
Value: 0.6

Hope this helps!

[Poonam Jindal]

Hi Scott

Yes it worked out 🙂
Thank you so much, it is really a great help !!

Sir, I am trying to design a 2D Photonic Crystal based Y junction Power Splitter using optiFDTD.
I also wanted to know that can we design a 2D hybrid structure i.e a combination of hexagonal and rectangular lattice structure on optiFDTD. In crystal lattice properties- lattice properties-type- 2D Rectangular, 2D hexagonal, 3D rectangular, 3D Hexagonal, FCC,BCC options are there only. so how to design a hybrid structure.

[Scott Newman]

Hi Poonam,

There is not a direct hybrid crystal option but this can be done by carefully creating multiple crystals and overlapping them. This solution does depend on the specific design you are implementing. Do you have a paper or reference I could see?

Scott

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