Spiral Shaped Photonic Crystal Fiber-Based Surface Plasmon Resonance Biosensor for Cancer Cell Detection
, Vladimir V. Demidov 4, Juan Yin 7, Ghanshyam Singh 8 and Manish Tiwari 1
Round 1
Reviewer 1 Report
The article reported by Mittal et al. shows a numerical investigation over plasmonic PCF based refractive index sensors utilising thin Au film. The article is purely numerical analysis but has some potential, however, there are some open points that need to be addressed before any consideration. Comments are given below:
- State of the arts need to be improved. There are several articles reported in past decades on SPR sensors however author fails to address the need of the reported technology over the other with high sensing performance. For instance there are some article achieves three to four time higher sensitivity such as 10.1109/LPT.2020.2980470, 10.3390/s21030818, 10.1016/j.rio.2022.100223, etc. authros are advised to compare why they choose to design such sensor which provides the poor performance then some of these reported articles.
- It seems like phase matching point in Fig. 4 is beyond the maximum confinement loss. Authors are advised to draw a line to show they are aligned to each other. At the phase matching point the energy is completely transferred from core mode to SPP mode and gives the maximum modal loss while as I can see from Fig. 4, the maximum loss is obtained a bit away from the phase matching point, why so? reason must be discussed.
- Fabrication tolerance must be included in the result and discussion for each parameter. See article: 10.1007/s11082-022-03779-5
- It’s actually a refractive index sensor which can be used as biosensor. Since there’s no experiment has been performed I recommend author to remove all the medical terms including biosensor, cancer, etc from the article. It may mis lead the audience.
- Dispersed typos and grammatical errors.
Author Response
Please see the attachment."
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this manuscript, a spiral-shaped photonic crystal fiber (PCF) based surface plasmon resonance (SPR) has been proposed and the proposed sensor can respond six cancer cells. In addition, the maximum sensitivity of the sensor is -289 RIU-1 for the refractive index of the detection of breast cancer cell with the resolution of 2.33x10-4. I have some comments to do after reviewing this manuscript, details are as follows:
1. Please check the manuscript again, it has some format problems. (Such as, line 57, 94, 102.)
2. In Figure 4, why X-polarized fundamental mode and Y-polarized fundamental mode produce exactly the same confinement loss for SPR excitation, please explain it clearly.
3. Figure 5 tests separately different cancer cells, when different cancer cells are mixed together, can they be distinguished simply by amplitude sensitivity?
4. The introduction can be improved. The articles related to some applications of Photonic Crystal Fiber should be added such as Phys. Chem. Chem. Phys., 2022, 24, 21233; OPTICS LETTERS, 2018, 43(4), 891-894; NATURE PHOTONICS 8(4), 278-286; Optics Express 2022, 30, 39056.
5. The manuscript needs to add some physical explanation for the phenomenon, the manuscript has basically only description without explanation.
Author Response
Please see the attachment."
Author Response File: Author Response.pdf
Reviewer 3 Report
The authors propose a new optical sensor that is based on a surface plasmon resonance effect on a spiral-shaped photonic crystal fiber structure. The author claims that the proposed optical sensor has a linear sensor response. I feel that work addresses an important topic especially because of its possibility to detect breast cancer cells with greater resolution. I recommend publication after a few major points are considered.
1. The author claims that the sensors show a linear response. But is this linear response limited to the wavelength region? If that is the case, it will be good from the reader's standpoint to know how the sensor will perform on the other wavelength as well.
2. How does the sensitivity vary with the thickness of the gold layer?
3. Is there any dependence of the polarization of the light on the sensitivity of the sensor?
Author Response
Please see the attachment."
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The author has addressed all the raised concerns positively, hence I recommend its publication in Photonics. Good luck
Reviewer 2 Report
Accept in present form.
Reviewer 3 Report
The authors have addressed my concerns in this paper. The quality of the paper has improved after the second revision and I agree to accept the paper in the present format.
