Enhanced Power Distribution and Symmetry in Terahertz Waveguides Using Graphene-Based Power Dividers

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The author proposed the plasmonic power divider at the THz region by using the graphene on insulator system. However, there are some issues weird to me.

1, Why did the authors choose the width of the plasmonic waveguides, especially the width of the input waveguide? Is this the multiple waveguide? Or the single mode waveguide?

2. According to the E field distribution of the propagation of the plasmon along the proposed device, the EM fields is mainly confined at the interface between the edge of the waveguides and the free space, which may induce the scattering of the plasmon while propagation.

3. The author did not provide the propagation loss information of their structure.

4. The author did not show the comparison between their structure and the reported devices investigated by other groups.

In conclusion, the author failed to demonstrate the novelty of their study, whereas the calculation results are weird to me. Thus, I could not recommend the acceptance of this manuscript.

Comments on the Quality of English Language

The English is OK to me. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

 

This paper delves into the design and optimization of a graphene-on-insulator power divider tailored for terahertz applications, leveraging the principles of spoof surface plasmon polaritons. This research reveals that the incorporation of three graphene layers notably enhances power distribution and output port symmetry. By modulating the graphene chemical potential within a range of 0 to 0.5 eV, they demonstrate dynamic electrical control over the waveguide's transmission properties. This innovative device presents promising prospects for applications in plasmonic circuits and on-chip interconnects that operate within the terahertz frequency spectrum. This manuscript is worth to be accepted for publication in Photonics. My comments are listed below.

 

1. How was the design of this structure approached? What rationale led to the specific geometric configuration and dimensional parameters chosen?

 

2. Why were three graphene layers selected? How can they be modeled in simulations? What are the fundamental differences in physical properties compared to a single layer of graphene?

 

3. In practical scenarios, how can the chemical potential of graphene be dynamically controlled? Is it through the application of a bias voltage? Particularly with three graphene layers, wouldn't there be significant challenges in actually regulating the chemical potential?

 

4. What advantages does the Graphene-Based Power Divider proposed in this paper have over other types of Power Dividers? It is suggested to compile a table for a comprehensive performance comparison.

 

5. Although this paper presents a purely simulated design, it is necessary to briefly discuss the feasibility of implementing such a design experimentally and what challenges still remain.

 

6. In the introduction, it is crucial to mention recent advancements in graphene-based electromagnetic devices. For instance, L. Shao et al. reviewed on the emerging applications and properties of graphene-derived microwave metamaterials and meta-devices (Electron, 2, e60, 2024). Q. Li et al. presented a graphene-based optically transparent metasurface for microwave and terahertz cross-band stealth (Carbon, 219, 118833, 2024).

Comments on the Quality of English Language

Good.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

The authors theoretically examined a graphene-on-insulator power divider at THz frequencies and proved that utilizing three graphene layers significantly enhances power distribution and symmetry at output ports. While the concept is interesting, the manuscript requires additional discussion on the following issues:

1.      In the introduction, it is worth briefly mentioning other (apart from graphene) materials responding to external stimuli that can potentially be used to control terahertz radiation, e.g. liquid crystals (Liquid Crystals, 43(8), 1120–1125 (2016)), VO₂ ( Nanomaterials 11.1 (2021): 114), etc.

2.      The simulation description should be detailed. What electromagnetic simulator was used, what was the size of the numerical grid in each dimension, what was the distance of the ports from the structure? The description should enable reproducing the results.

3.      What effect will the dispersion of individual material parameters have on the device parameters? Did the authors take this into account in their simulations?

4.      The authors wrote “In the proposed structure, a dielectric with a refractive index of n=2 is considered.” What was this dielectric, what material has such a refractive index in a specific spectral range? Please indicate a specific dielectric. The device concept must give hope for implementation.

5.      What I miss here is a specific theoretical analysis of the device. The results are very poor. Half of the article is basically an analysis of graphene itself, not a device that uses graphene. Please take a look at what a reliable article looks like: IEEE Access 8 (2020): 214425-214433; Optics Letters 49.19 (2024): 5579-5582; etc.

Despite the many shortcomings mentioned above, I give the authors a chance to improve the article, which must be thorough and reliable. Otherwise, the manuscript will not be suitable for publication.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

All my concerns have been well addressed. Acceptance is recommended.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors responded to my comments in great detail and revised the manuscript. Therefore, I believe that the manuscript should be published in its current form.