KNbO3 diffused material declaration

[rabeya shompa]

Hlw,
I need to define KNbO3 as diffused material. For that i had to change ordinary and extraordinary reftractive index. I could not change ordinary refractive index as it is shown as by default. See lesson 7 for realising my problem. Can anyone tell me how can i change ordinary reftractive index? Please…

[rabeya shompa]

see the figure. i also need to change the constant r22 into r12. how do i do it?

[Ravil]

Hello rabeya shompa,

Welcome to the Optiwave forum! According to your question, you should be able to change your ordinary refractive index before setting up electrooptic coefficients. If I am not mistaken, you should be able to do it under the “profile” tab, when you going to the “diffusion” folder for KNbO3.

[Ravil]

Dear rabeya, I am not quiet understand what do you mean by “change the constant r22 into r12”? Do you mean that you just want to rename it and pass the value. It is known that electrooptic coefficients are related to index ellipsoid. Therefore, they are unique for each material and define its optical properties.

[rabeya shompa]

Dear Ravil,
when i tried to define KNbO3 under profile tab the material dialogue box look likes the image in my comment. You can see that ordinary refractive index is blurred because it is by default. To change extraordinary refractive index i just vanised the tik mark in the auto box … but for ordinary one there was no scope to do it. Let me know if there is another way…i choose z crystal cut and y propagation direction. If i choose x cut crystal then ordinary index can be changed but no extraordinary. I need a z cut crystal and i have to change both ordinary and extraordinary. Thanks

[Ravil]

Dear rabeya shompa,

Just want to confirm one more time, if you tried to make a change of ordinary refractive index in the “Diffusion” section, which is located under the “Profiles” tab. According to your uploaded picture, for me it looks like you are trying to make the change of your ordinary refractive index under the “Materials” tab. Unfortunately, I don’t have an OptiBPM “at a hand” to check it myself.

[Ravil]

According to your question about the cut and refractive indices that you can change for some particular cut that you choose, I would like to remind you that the orientation of the field of propagating light with the optical axis defines the speed of light propagating through the material. Therefore, please, check the direction of light propagation and compare it with your index ellipsoid picture.

[Ravil]

However, according to the geometry of ellipsoid, the selection of your electrooptic coefficients will depend on your crystal cut and the light propagation directions. Please, let me know if it helps in your situation.

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