Learning Forum

[ph23resch01002]

I am attempting to replicate the findings of the study by Hail, C.U., Foley, M., Sokhoyan, R. et al., titled "High quality factor metasurfaces for two-dimensional wavefront manipulation," published in Nat Commun 14, 8476 (2023). I have conducted simulations on the transmission and reflection properties of the meta-atom, and the results somewhat aligns with those reported in the article. Both sets of results, from the article and my own simulations, have been included as attachments. Now, I aim to measure the quality factor of the transmission curve. To achieve this, I utilized a low Q-analysis group from the object library. After adjusting the position of the time monitor, I executed the analysis group. However, the Q-Factor obtained is significantly larger compared to the Q-Factor presented in the article. Q-Factor, from article is 290 whereas after running the analysis group, I am getting, Additionally, I will attach screenshots of the results after running the analysis group. (I get resonant dip at 1281nm as per Figure 2 but the low-Q Analysis group shows resonance at 1691nm and the Q factor is very large)

 

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[Guilin Sun]

It seems the transmission and reflection curves you simulated (bottom figure) are similar to the publication (up figure). Usually it is better to check the reflection instead of transmission since the latter has a dip. You will need to find the point of 3dB level for FWHM.

There are different methods to calculate Q.

The low Q analysis group calculates the fft of the fields and computes the FWHM. Please check the script and make sure they work fine.

You can try to use findresonance: findresonances - Script command

You could also fit the result near the resonate wavelength

In addition, you may also try the high-Q analysis group.

The discrepancy appears when the resonance peak is not a Lorentizian shape.