Multipolar Analysis in Symmetrical Meta-Atoms Sustaining Fano Resonances

Round 1

Reviewer 1 Report

In this manuscript, the authors report a numerical analysis on the optical behavior of an all dielectric metasurface based on a square lattice of cylindrical nanopillars. The resonant behavior results in a strong suppression of the forward scattering associated to the excitation of different multipolar resonant condition depends on the lattice constant, which affects both the lineshape and the Q-factor of the resonances, revealing the collective response of the metasurface.

I have couple of comments as below:

1. In Figure 1c, at the pitch value 350 nm, absorption decreases dramatically.  

    But in the text it is mentioned absorption increases up to 40%.

2. Why at pitch value of 350 nm, the Q-factor resonance value is highest (1400), although at this pitch value, resonance almost vanishes.

3. The sensitivity of the metasurface is calculated as 0.71. Is it comparable  

    or better than to other metasurfaces? Some discussions need to be added.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors theoretically proposed optical metasurface with symmetrical individual elements sustaining Fano-resonances with high Q-factors at visible spectrum. In the manuscript, I noticed several issues that require deeper discussion. Therefore, I ask the authors to refer in detail to the following points:

1.     The abstract is written too general, which does not encourage potential interested parties. I suggest including in 1 sentence what results were achieved, etc.

2.     In the introduction, the authors focused on listing and briefly describing the possibilities offered by metallic and dielectric metamaterials. It is worth broadening this perspective and mentioning several metadevices’ concepts that have been presented in recent years, e.g. Sci Rep 9, 20367 (2019); Frontiers in Physics 8 (2021): 605125.

3.     Unfortunately, the description of the simulation is incomplete and makes it impossible to reproduce the results. How thoroughly were the properties of individual materials simulated and what models were used? Did the authors take into account the dispersion of material parameters? I also suggest inserting a table with material parameters (permittivities, losses) of individual materials along with the wavelength for which they apply and providing the source of these data.

4.     For greater clarity, I ask the authors to insert a table comparing the most important parameters of the presented Fano resonance metastructure with other similar ones. How can the Q-factor be further increased in the presented model?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

-          Could you comment on the possibility of using the proposed structure for broadband forward scattering? In this regard, I recommend to include the following reference:

[1] Barreda, Á.; Albella, P.; Moreno, F.; González, F. Broadband Unidirectional Forward Scattering with High Refractive Index Nanostructures: Application in Solar Cells. Molecules 2021, 26, 4421. https://doi.org/10.3390/molecules26154421

     Which is the mesh chosen in the simulations?

      Can you also provide the value of the figure of merit FOM and not only the sensitivity?

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The author proposes a metasurface and detailed research and analysis were conducted on it, before the paper was published, I think there were the following issues with the paper

1.      The author's mention of nanocolumns in the article seems to only mention their complex refractive index. Is there a suitable material in the current material system that could potentially enable the fabrication of this metasurface?

2.      In line 80, the author uses the classical asymmetry described in the Fano theory to explain the phenomenon when p is greater than 350nm, but the physical meaning of the Fano parameter is not mentioned throughout the text. In order to increase the readability of the article, I believe it is necessary to insert relevant formulas in the paper.

3.      In the introduction section, regarding metasurface, the author needs to mention some of the latest related work, such as, Diamond and Related Materials 142, 2024, 110793; Opto-Electron Sci 1, 210014 (2022); Opto-Electron Adv 5, 200098 (2022).

4.      Similarly, it is necessary to display important formulas when calculating the contribution rate in line 90. For example, the calculation formula for ED and MD.

5.      Has the author attempted to process the device? Are there any unresolved challenges during the processing of this device?

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors have addressed all my questions about the article. I support its publication 

Reviewer 4 Report

Accept.