Plasmonic Jackiw-Rebbi Modes in Graphene Waveguide Arrays
Round 1
Reviewer 1 Report
This work collects lots of data on the target subjects, and many exciting aspects are well included. The authors show many characterization data to support the claims. The manuscript is well organized. After the following minor revision, I can accept the publication of this paper. How about the material stability? It is better to add more comments on this. Related papers have been reported by different research groups. It is better to cite the following refs to support some related paragraphs in the introduction part. [Graphene - 2D materials][Graphene supercap] Chem Euro J, 20, 2014, 13838 (> 200)
Nature Chemistry 8, 638, 2016 (>200)
[Graphene/polymer composites for supercap] ChemSusChem, 7, 2014, 1551 (>100)
ACS Nano, 2018, 12, 5674, etc Overall the manuscript is well written, but I want to see the authors' perspective on this research in the conclusion part. Some little typo errors are found. Please carefully check the sentences again.
Author Response
This work collects lots of data on the target subjects, and many exciting aspects are well included. The authors show many characterization data to support the claims. The manuscript is well organized. After the following minor revision, I can accept the publication of this paper.
Respons: We thank the reviewer for the nice comment on our work.
How about the material stability? It is better to add more comments on this.
Response: Graphene shows stable mechanical properties thanks to the stability of the sp2 bonds that form the hexagonal lattice and oppose a variety of in-plane deformations. The chemical properties of graphene are quite stable and will not be easily oxidized. However, the optical properties of graphene change with the change of the dielectric environment in contact with it. For example, air components such as different concentrations of oxygen and water vapour may affect the chemical potential of graphene. The discussion is added， please refer to lines 31-38 in the revised manuscript.
Related papers have been reported by different research groups. It is better to cite the following refs to support some related paragraphs in the introduction part. [Graphene - 2D materials]
[Graphene supercap] Chem Euro J, 20, 2014, 13838 (> 200)
Nature Chemistry 8, 638, 2016 (>200)
[Graphene/polymer composites for supercap] ChemSusChem, 7, 2014, 1551 (>100)
ACS Nano, 2018, 12, 5674, etc
Response: The mentioned references are added in the revised manuscript, please refer to Refs. 11-15.
Overall the manuscript is well written, but I want to see the authors' perspective on this research in the conclusion part.
Response: In my opinion, the further studies can be carried out from the following three aspects. The first is the structure design by using graphene ribbon, which is easier to be fabricated in experiment than the planar graphene sheet. Secondly, whether the suitably distributed loss can generate Jackiw-Rebbi modes is also an interesting topic. Thirdly, one may extend the study to higher dimension, such as the two-dimensional graphene-coated nanowire arrays. The discussion is added in the revised manuscript, please refer to lines 204-209.
Some little typo errors are found. Please carefully check the sentences again.
Response: Thanks for the suggestion. We have made efforts to improve the English of the manuscript.
Reviewer 2 Report
The authors have investigated the topological bound modes of surface plasmon polaritons in graphene pair waveguide array with different chemical potentials, which are analogous to Jackiw-Rebbi modes. They have shown that the topological bound modes can be dynamically controlled by tuning the chemical potential and the propagation loss of the modes can be remarkably reduced by decreasing one of the chemical potentials. These results are very interesting for realization of graphene waveguide and are worthy to be published in this journal after the minor revisions shown below.
It is better to write the waveguide array numbers in Fig.1 to easily understand the sentences (n<0, etc.) in the lines 85, 86. In the line 157, Fig. 6(a) should be replaced by Fig. 5(a). In the line 163, “smallest” should be replaced by “largest” and “largest” should be replaced by “smallest”.Author Response
The authors have investigated the topological bound modes of surface plasmon polaritons in graphene pair waveguide array with different chemical potentials, which are analogous to Jackiw-Rebbi modes. They have shown that the topological bound modes can be dynamically controlled by tuning the chemical potential and the propagation loss of the modes can be remarkably reduced by decreasing one of the chemical potentials. These results are very interesting for realization of graphene waveguide and are worthy to be published in this journal after the minor revisions shown below.
Response: We thank the reviewer for the nice comment on our work.
It is better to write the waveguide array numbers in Fig.1 to easily understand the sentences (n<0, etc.) in the lines 85, 86. In the line 157, Fig. 6(a) should be replaced by Fig. 5(a). In the line 163, “smallest” should be replaced by “largest” and “largest” should be replaced by “smallest”.
Response: Figure 1 is replotted and the mentioned mistakes are corrected.
Reviewer 3 Report
Authors mention in the the abstract that “This Study provides a promising approach to realizing robust light transport beyond diffraction limit”, but it feels like this part wasn’t explained properly in the results and discussion part. May be giving some example to compare would make the case stronger.
The findings of the paper are good, which shows chemical potential as tuning parameter, and also showed the effect on the “Real” and “Imaginary” part of “effective refractive index”. But, For Figure (2), authors chose chemical potential of 0.18 eV and later they varied chemical potential between 0.13 to 0.17 eV. It would be a better representation if they show the effect over broader range of chemical potentials.
For the graphene waveguide arrays study (2.2), some parameters were fixed (line 102), it would be better if authors put some explanation on choosing these specific values and their significance.
Overall, the manuscript is acceptable, with some minor changes as indicated and some more explanation on applicability of this study to justify the propositions in the abstract.
Author Response
Authors mention in the the abstract that “This Study provides a promising approach to realizing robust light transport beyond diffraction limit”, but it feels like this part wasn’t explained properly in the results and discussion part. May be giving some example to compare would make the case stronger.
Response: The topological bound modes are extremely robust against structural disorder. To test the robustness of Jackiw-Rebbi modes, we consider the chemical potential of originally graphene sheet arrays is m1 = 0.15 eV and m2 = 0.18 eV, the corresponding surface conductivity are s1 and s2, respectively. We further introduce the disorder into them by defining a random fluctuation of the surface conductivity. The additional surface conductivity of nth graphene sheet is set to be a random value dn, which is smaller than (s2 -s1)/4. Figures 6(a) and 6(b) plot the real and imaginary part of effective refractive index for one disordered structure. The results show that the band gap does not close and the Jackiw-Rebbi persists in the gap. The discussion is added in the revised manuscript, please refer to Fig. 6 and lines 183-190.
The findings of the paper are good, which shows chemical potential as tuning parameter, and also showed the effect on the “Real” and “Imaginary” part of “effective refractive index”. But, For Figure (2), authors chose chemical potential of 0.18 eV and later they varied chemical potential between 0.13 to 0.17 eV. It would be a better representation if they show the effect over broader range of chemical potentials.
Response: Figure 5 is replotted with the chemical potential ranging between 0.12 to 0.19 eV.
For the graphene waveguide arrays study (2.2), some parameters were fixed (line 102), it would be better if authors put some explanation on choosing these specific values and their significance.
Response: The parameters of graphene parameters are typically used for simulation (Phy. Rev. Lett. 109, 073901, 2012), which coincides with the experiment. The spacing is fixed at d = 70 nm such that the graphene sheets are weekly coupled. Please refer to lines 114-115.
Overall, the manuscript is acceptable, with some minor changes as indicated and some more explanation on applicability of this study to justify the propositions in the abstract.
Response: We have carefully addressed all the issued proposed by the reviewer.
