All-Dielectric Dual-Band Metamaterial Absorber Based on Ring Nanocavity in Visible Region for Sensing Applications
Round 1
Reviewer 1 Report
The authors have demonstrated metamaterial absorbers for sensing applications, which is inspiring. However, some questions and comments should be addressed before publication.
1. Are there any experimental data to support the simulated and numerical results?
2. Is the width increase linearly related to the blueshifts of the peaks? Is there a limit on that?
3. Are there any reasons that there are side peaks in figure 5 at n=1.08 and n=1.04 compared to n=1?
4. Please delete the dash lines around for figures and centralize the figures properly.
Author Response
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Reviewer 2 Report
Figure 3 shows the result of the electric and magnetic field distribution simulation. Unfortunately, the scale (colorbar) does not show any numerical values, only the relative change. Such a presentation does not give any information about the intensities or the gradient of the fields. Whether the fields between the min and max values change only by 0.0001% or by 1000000000 times, the drawing looks identical. It is therefore not possible to determine the significance of these results and the actual expected value of the electric and magnetic field concentration for such a structure. This information also does not appear in the discussion. In order to fully understand the results of the simulation of the distribution of electric and magnetic fields, it is necessary to provide numerical values for the nim-max range presented in Figure 3.
Author Response
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Reviewer 3 Report
The authors developed the concept and theoretical model of the all-dielectric dual-band metamaterial absorber in visible region. After a thorough evaluation of the manuscript, I think that the scheme of the device is interesting and quite simple in construction, thanks to which it creates real prospects for later experimental research. However, the current version of the manuscript requires more in-depth discussion of several important issues:
1. The abstract in its current form is too general. It is worth including some of the most important parameters of the device.
2. The scheme of the device (i.e. Fig. 1.) is too low resolution. It is worth taking more care of the graphic side of the manuscript.
3. In recent years, many concepts of various metamaterial absorbers have appeared. Therefore, in the introduction, it is worth presenting a broader point of view on various directions of research on these devices and, more importantly, justifying the advantages of the presented concept against the background of other meta-devices. What features make this concept unique? It is true that the authors have included a table, but it is not sufficient to fully justify it.
4. In my opinion, the main limitation of the presented concept is the fact that the absorber is static and passive. As a result, it is worth discussing whether the presented concept gives the possibility of its expansion and obtaining tunable absorption? Please see: Nanomaterials 12.16 (2022): 2849; Liquid Crystals 46.10 (2019): 1568-1573; Optics Express 25.20 (2017): 23873-23879; Optics Communications 369 (2016): 89-93, etc.
5. How does the change in Si thickness affect the parameters of the device? Please add a chart.
6. The distribution of the electric field (Fig. 3.) should be more accurate and show the individual components of the field (Ex, Ey, Ez).
Author Response
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Reviewer 4 Report
In this manuscript, a dual-band metamaterial absorber based on an all-dielectric structure consisting of a silicon-based ring nanocavity array, a SiO2 layer and aluminum film was investigated. The electromagnetic response characteristics of the absorber were numerically studied. The proposed all-dielectric dual-band metamaterial absorber was then used as a refractive index sensor. The refractive index sensitivity of 200 nm/RIU and FoM of 65.3 was obtained with the all-dielectric dual-band metamaterial absorber.
The reviewer has the following comments and suggestions:
1. Is there a reason why use aluminium film as the metallic substrate? What about Au and Ag films?
2. Only the effects of width of nanocavity on the absorption spectrum and sensing performances were studied in this manuscript. The effect of other structural parameters, such as lattice constant, outer and inner radius of the ring nanocavity, and thicknesses of the hollowed Si film and SiO2 layer, on the on the absorption spectrum and sensing performances should be discussed.
3. “Obviously, C will increase with w, which would then lead to a decreased resonance wavelength (blue shift) at the resonant peak.”. Please explain this in more detail. For example, what is the relationship between the capacitance C and the resonance wavelength?
4. In Fig. 4b, why the FWHM increases with the width of nanocavity?
Author Response
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