J point in triangular photonic crystal


#1

Hello, All.

I want to see the resonance frequency at J point in triangular photonic crystal (Fig.1).
Please tell me the plan for this.

image
Fig.1 Triangular photonic crystal and the band structure
(“Multidirectionally distributed feedback photonic crystal lasers”, Masahiro Imada, et al., PHYSICAL REVIEW B, VOLUME 65, 195306 (2002))


#2

Hi @d8822002

We have plenty of examples on how to calculate the bandstructure of photonic crystals:
https://apps.lumerical.com/diffractive_optics_pc_bandstructure.html

For every specific point in the bandstructure, you need to set the corresponding kx, ky, and kz values from the FDTD->Bloch boundary conditions tab and then use DFT monitors to capture the field profile similar to what we have done in this example:
https://apps.lumerical.com/diffractive_optics_pc_bandstructure.html


#3

Thank you, for your answer.

First, I calculated the bandstructure of Fig.1.
The result is Fig.2.

image
Fig.2 The result of calculating the bandstructure

Next, I calculate the resonance frequency at J point [Fig.3].
The result is Fig.4.


Fig.3 FDTD boundary condition


Fig.4 The resonance frequency

These resonance frequency spectrum should match with Fig.2, but it does not match.
Why?


#4

Hi @d8822002

Did you obtain Figure 2 from the simulations? If yes, Figure 2 essentially uses data from Fig.4 and I am surprised why they are not the same. One possibility is that you are using a smller num-band in the script used for post processing. Please share your simulation files for a review if you still had any problem.

Thanks


#5

Thanks for your reply.

These are my simulation files.

tri2D_2D_for_bandstructure.fsp (3.5 MB)
tri2D_2D_for_bandstructure.lsf (2.8 KB)
These simulation files are used for calculating the bandstructure(Fig.2).

Tang_cavity_60000fs_Jpoint_for_resonance.fsp (384.0 KB)
This file is used for calculating the resonance frequency(Fig.4).

Please check these simulation.

Thanks.


#6

Hi @d8822002

I am not sure if I understand your approach completely. The fig.2 in the previous post is obtained from tri2D_2D_for_bandstructure.fsp file while the spectrum is obtained from Tang_cavity_60000fs_Jpoint_for_resonance.fsp? If this is the case, you need to compare the two simulation files and see what is different between them. Once you figured it out, then you can obtain the spectrum at a specific point in the bandstructure as I explained on my first reply.