High-Q Resonances Enabled by Bound States in the Continuum for a Dual-Parameter Optical Sensing

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

see attached

Comments for author File: Comments.pdf

Author Response

Please see the attachment. The manuscript with revised sections highlighted in red is uploaded in Non-Published Material.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In this manuscript, the authors proposed an all-dielectric grating for ultrasensitive refractive index and temperature sensing. The grating in the near-infrared wavelength band can support two sharp resonances, including a quasi-BIC mode and a Fano-type mode. Through numerical calculation, the two resonances exhibit ultrahigh sensitivity regarding ambient refractive index and temperature variations. The designed grating has exceptional performance advantages in temperature and refractive index sensing due to its high Q-factor and high sensitivity. This work provides a feasible solution for dual-parameter sensing with ultra-high sensitivity through high Q-factor resonance, making it applicable to miniaturized high-precision sensing applications. However, there are still some important issues to be addressed before it is suitable for publication.

1. In the abstract, all abbreviations (e.g., quality factor, Q) must be defined in full upon first use. The content should be concise, emphasizing the research significance and key contributions, while avoiding mention of specific simulation software names.
2. A more rigorous comparative analysis between BIC sensing and established techniques is recommended to be incorporated in the Introduction. The current discussion is presented in an oversimplified manner regarding technological advantages, which diminishes the justification for adopting BIC-based approaches. Explicit comparisons of physical mechanisms and their implications for sensitivity are strongly recommended to be addressed.
3. The current manuscript lacks clarity in describing multiple parameters (e.g., refractive index sensitivity, temperature sensitivity, and FoM values for both BIC and Fano resonance modes), which may confuse readers. Please revise the text to enhance clarity.
4. Please add the transmission spectra of the grating as a function of the asymmetric parameter δ (e.g.,δ varies from 0 to 120 nm with a step of 10 nm), clearly illustrating the transition from an ideal BIC to a quasi-BIC with increasing δ.
5. The current comparative analysis in Table I lacks sufficient data points to convincingly highlight the advantages of the proposed grating sensor. It is recommended to expand the table with more data, as well as add the results of this work.
6. The font size in all the figures should be appropriate to ensure that they can be clearly shown.In addition, the parameter “d” in Figures 2 and 3 needs to be replaced by the asymmetry parameter “δ”.

Author Response

Please see the attachment. The manuscript with revised sections highlighted in red is uploaded in Non-Published Material.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This study introduces a dual-parameter all-dielectric transmissive grating sensor that combines symmetry-protected bound states in the continuum (BICs) and Fano resonance for high-precision refractive index and temperature sensing. Using COMSOL Multiphysics simulations, two resonant modes were identified: Mode I, a BIC with high sensitivity to refractive index and temperature, and Mode II, exhibiting Fano resonance with stable quality factors. The sensor shows excellent performance, offering high Figures of Merit (FoM) for both parameters, making it suitable for applications in lab-on-a-chip systems and biomolecular monitoring.

Overall, the study looks promising, but I have a few questions before making a final decision:

1. Could the authors provide more details on how they calculated Figure 3b?

2. How did the authors derive the relationship in Equation 1, and what approach did they use to arrive at it?

Author Response

Please see the attachment. The manuscript with revised sections highlighted in red is uploaded in Non-Published Material.

Author Response File: Author Response.pdf