Simulation of transmittance through a colloidal photonic crystal slab

[Serena Zhang]

I need to simulate optical response (mainly transmittance and reflection) through colloidal photonic crystal slabs. The slab is uniform with spheres filled inside the medium. The slab is about 10-50um thick. I am very new to FDTD. Any suggestions here?

[Aurelien Duval]

Hi,

It seems doable using our software. The approach will really depend on how these spheres are organized.

If you have a regular pattern, then drawing the photonic crystal will be pretty simple. You just need to use the photonic bandgap crystal tool (PBG tool) to define your lattice and atoms.

If it’s a random suspension of colloids, then we’ll need to use scripting to drive the position of each sphere according to an equation.

I can find you some examples of both types if needed.

[Serena Zhang]

Thank you for your response. That would be great if you can find me some examples. I need to decide if we should purchase the software or not. I am not sure if FDTD is a good method for simulating optical response of a limited thickness PhC slab.

[Aurelien Duval]

Hi,

Here are a couple of examples.
You will have to adapt them to your specific application, but that’s the general idea.

* colloidal_phC_hexa_pavement.fdt : a regular 3D hexagonal lattice or air holes in a dielectric material
* vbColloidal_phC.fdt : a randomly-distributed (in position and sizes) colloidal suspension of air bubbles in a dielectric material (like a sol-gel for example). This example uses visual basic scripting to position the bubbles.

I hope you will find them useful

Aurelien

[Serena Zhang]

Hello, Aurelien

Thank you again for the examples. I have one more question. I have measurement data (transmittance from Cary 50 and specular reflection by Lambda 900). How can I correlate the simulation from FDTD with the measurement data? Right now, the simulated power spectrum at the transmission detector is so low. It doesn’t seem to increase much no matter what parameters I change (e.g. index contrast, layer number, etc).

Can you take a look for me? The colloidal photonic crystal slab I am working on has very low index contrast (delta n <0.1) between the spheres and the matrix, but has a good periodic structure. The sphere radius is about 60-80nm. I am trying to find out how optical spectra will change with sphere size, filling factor, layer number, and disorder, etc.

[Serena Zhang]

Hi, Aurelien

Great. The first example is very similar to to what I am planning to design. I am still learning to use the software. But I will let you know how it turns out.

Many thanks.

Serena

[Aurelien Duval]

Hi,

I would be happy to help you, but I would more specific information about the samples you have to see if we can match the measured values. Do you have sample images or drawings showing the distance between spheres, number of layers etc? Could you also send me the actual measured curves? Finally at which wavelength range where these measurements taken?

If you are afraid to share data on the forum you can always email me at : aurelien.duval (at) optiwave.com

[Serena Zhang]

Great. I just sent some files to your email. Thanks again.

[Serena Zhang]

Hello, Aurelien

I am wondering if you’ve received my email with the original data. My 64-bit trial license is expiring, but I haven’t been able to simulate anything close to the measurement data. There are too many layers in the z-direction (>80 layers and 15um thick). Will FDTD be a good solution for this type of structure?

[Bryan Tipper]

Serena,

This post was randomly drawn as the winner for our June Samsung Galaxy Tab 3 giveaway. Congratulations!!!

Please email us at info@optiwave.com to let us know where you would like the Galaxy Tab shipped.

Thanks,
Bryan

[Luis Acevedo]

Congratulations Serena

Enjoy the Samsung Galaxy Tab 3

cheers

[mohammed mostafa]

Congratulations Serena

[Luis Acevedo]

🙂

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