Generation of Polarization Independent Ring-Airy Beam Based on Metasurface

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In the current manuscript, the authors presented a polarization independent ring-Airy beam generator based on metasurface. The metasurface is designed to modulate both amplitude and phase of transmitted light, and the auto-focusing, self-healing and frequency-response features of airy beams are verified. The authors are suggested to address the follwoing several issues before the acceptance.

1. In line 44, the authors claimed that “every antenna unit is composed of two orthogonal subwavelength metallic rectangular slits”. However, the unit cell shown in Fig 1.(a) only has one slit. Please further explain the composition of unit cell and how the unit cells are arranged.

 

2. In terms of the self-healing feature of airy beam, only one case is simulated. If the obstacle is moved along the x-y plane, whether it still has this feature or deteriorate? More cases are suggested to be discussed.

3. The features of airy beams varified in the current manuscript are commonly discussed in previous works, are there any new features or performance improvements in this work? The authors are suggested to further explain the novelty of this work.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The paper proposes a design to generate the Airy beam using gold slits. The authors discussed the design of the metasurfaces, the intensity distributions of the generated Airy beam and also the frequency response. The results are complete and solid. However, there are a few points I think the author should clarify before I could recommend the article to the Photonics:

1. The author should state clearly about the novelty of the design. Metasurface (no matter it is plasmonic or dielectric) could arbitrarily control the amplitude and phase by changing its shape and rotating its angle. This is a well-known design strategy in the community and there are numerous papers demonstrating it. This design is also an application of it. In addition, using plasmonic metasurface to design the Airy beam has been proposed before[1,2]. The author should state the advantage of using their design.

2. The discussion of the frequency response could be expanded. The article uses two wavelengths as examples to show the performance of the Airy beam. It is better if the author could explore the fractional bandwidth of the design and compare with other metasurfaces[3].

Overall, the article shows convincing evidence that the design will generate flexible Airy beams in various frequency and focal length, but the comparison with other design strategies and material platforms needs to be further clarified.

[1]Li, Zhi, et al. "Plasmonic airy beam generation by both phase and amplitude modulation with metasurfaces." Advanced Optical Materials 4.8 (2016): 1230-1235.

[2]Chen, Lin, et al. "Polarization‐independent wavefront manipulation of surface plasmons with plasmonic metasurfaces." Advanced Optical Materials 8.22 (2020): 2000868.

[3]Guo, Wen‐Long, et al. "Airy beam generation: approaching ideal efficiency and ultra wideband with reflective and transmissive metasurfaces." Advanced Optical Materials 8.21 (2020): 2000860.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper is dedicated to generation of polarization-idependent beams. The authors propose the design based on a metasurface comprising multiple nanoslits of two different orientations. Numerical results are presented in the paper. The paper can be interesting for journal reader but needs revision at this stage. 

The following issues should be addressed in the revised manuscript: 

1) the authors present only numerical results, so a possible fabrication procedure should be briefly discussed in the text  2) moreover, it should not be written (in contrast to that done in Abstract), that "such metasurfaces are fabricated by etching ...", because the authors do not report any fabrication or experiment results; it could be written "can be fabricated", but this should be rather a part of the brief discussion mentioned in 1), not a part of Abstract.   3) the meaning of "equal phase retardation" should be explained for wide reader  4) the meaning of "respectively" in the second sentense of the Abstract is unclear (what with respect to what?); anyway, it is recommended to carefully revise the Abstract  5) the authors are invited to explain why a metasurface based design may be preferable, compared to other possible designs, and give more information (mainly for wide reader) regarding the structures, which may enable Airy beam generation  6) in addition, generation of Airy beams must be considered in the context of a wider problem of generation of the beams of different types; therefore, some other approaches/classes of the structures, which are quite widely used for generation of the beams of different types in different parts of electromagnetic spectrum should be mentioned; some literature should be cited and briefly discussed: Jackson, D. R., et al. Proceedings of the IEEE, 99(10), 1780-1805 (2011); Habib, M., et al. Plasmonics, 14, 721-729 (2019); Podilchak, S. K., et al. IEEE Antennas and wireless propagation letters, 12, 665-669 (2013); Vertchenko, L., et al. Optics Express, 25(6), 5917-5926 (2017); Sharma, V., et al. Optics Express, 30(2), 1195-1204 (2022)   7) from the Abstract, we may learn that the structure's unit cell contains two orthogonal slits, but we see only one slit in the inset in Fig. 1(a); please clarify, how the studied metasurface really looks like   8) Line 47: which phase and magnitude are targeted? Below (lines 70-71), we learn that a binary phase distribution is needed for this particular Airy-beam functionality; please explain for wide reader (especially for that familiar with gradient metasurfaces) the reason why a binary phase is needed and what is the main difference compared to the gradient metasurfaces, which usually need multiple phase values between 0 and 360 degrees; e.g., see ref. 11 and ref. 21 from your literature list, as well as  Kang, M., et al. Optics express, 20(14), 15882-15890 (2012) and Khorasaninejad, M., et al. Nano letters, 16(11), 7229-7234 (2016)   9) please clarify what is the wavelength value in Figs. 2 and 3   10) please explain for wide reader the meaning of the term "self-healing" in the context of the targeted functionality  11) Line 167: which "two types of metasurfaces" are meant here? The explanation is needed; perhaps, you mean two different designs or performances?  12) Lines 163, 183: reword "we realize"; "realize" is commonly used when experimental realization is reported, but this is not the case here  13) the Conclusion section should be enlarged   14) Line 181: the meaning of "frequency-response properties" should be clarified; perhaps, another term is more suitable here  15) in Author Contribution "" at the beginning and at the end of the section are not needed   16) References should be carefully checked; for instance, issue/pages information is not given in refs. 10 and 25; in ref. 14, the first names and family names are mixed, e.g. Mohammadreza and Federico must be the first names, not the family names of the authors   17) Double check the correspondence of the plots, figure captions, and related text for all figures 

Minor corrections:

Line 22: Siviloglu et al. 

Line 59: add "incident" between "RCP" and "light"

Line 110: this is rather "size", not "period" of unit cell

Line 165-166: "a=0.01" is duplicated, omit it in one of the two cases 

Line 180: add "numerically" between "have" and "demonstrated"

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors' response answers all my questions. I do not have more questions and I recommend the paper to be published.

Author Response

Thank you for your suggestions to improve our work.

Reviewer 3 Report

Comments and Suggestions for Authors

I appreciate the efforts of the authors. The manuscript is now in a better shape and can be recommended for publication. Prior to it, two minor issues are worth to be considered. The authors should double check the text: some words seem to be wrongly written e.g., "reflaction". Epecially, the new parts of the text should be carefully checked. Besides, the authors did not cite (and did not discuss) the paper Habib, M., et al. Plasmonics, 14, 721-729 (2019) and probably some other recommended papers that are dedicated to beam forming in different parts of electromagnetic spectrum.

Author Response

Please see the attachment.

Author Response File: Author Response.docx