Thermal Damage Characterization of Detector Induced by Nanosecond Pulsed Laser Irradiation

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

These authors study the experimental and simulation analysis was conducted on the effects of 532 nm nanosecond laser-induced thermal damage on the front-side illuminated CMOS detector. The study examined CMOS detector output images at different stages of damage, includ- ing point damage, line damage, and complete failure, and correlated these with microscopic structural changes observed through optical and scanning electron microscopy. There are still critical issues to be well addressed after minor revision before its formal publication in this journal:
1. The figures was not notice clearly for the readers are very hard to clearify the relationship of the figures.
2. I suggest all the figures should show the scalebar for better contrast and discussion.

The manuscript reveals the origin of CMOS damage by different intensity optic/thermal injection. It shows useful for next generation CMOS protecting project. With expection for the paper recieving after minor revision.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript entitled “Thermal damage characterization of detector induced by nanosecond pulsed laser irradiation” entails an interesting concept. The authors studied the thermal damage mechanism of 532 nm nanosecond laser on FSI CMOS detectors through experiments and simulations. For the benefit of the reader, some information requires further explanation. There are given below.

1. The word “detector” should be “detector”. Please revise it.
2. In Line 107, the authors assume that material properties remain constant with temperature changes. In Line 195, the manuscript mentions that the maximum temperature in the CMOS reaches 1750K. As a typical semiconductor material, the resistivity, conductivity, and thermal conductivity of silicon exhibit nonlinear changes with temperature, and the dominant mechanisms in different temperature ranges differ significantly. ‌‌ Please explain why this assumption holds true and how the simplification affects the simulations, especially under high energy density.
3. Please provide information on the spot diameter and laser repetition rate. These parameters may affect the thermal accumulation effect.
4. Please improve the resolution of Figure 10.

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

This paper experimentally and numerically investigates the thermal damage mechanisms of front-illuminated CMOS image sensors under 532 nm nanosecond pulsed laser irradiation. The overall structure is complete, the topic has certain engineering significance, the combination of text and figures is clear, and the data is relatively detailed. However, there are still many questions and areas for improvement in terms of the rigor of experimental design, the rationality of simulation model assumptions, the definition of damage criteria, the depth of literature citation, and innovation.

1. Typographical error in the title: "Detecor" should be corrected to "Detector."
2. The abstract lacks quantitative data to support the distinctions between damage stages (point, line, and complete failure).
3. The literature review is outdated and does not adequately reflect recent advancements in laser-induced damage to imaging sensors. There is a lack of discussion on research gaps.
4. Details about laser energy measurement are insufficient. The calibration method and measurement accuracy are not mentioned.
5. The damage classification criteria are ambiguous. The study relies solely on visual changes in output images without defining clear, repeatable, and quantitative thresholds.
6. Subjectivity in interpreting output images. No grayscale analysis, contrast degradation metrics, or signal-to-noise ratio evaluations are provided to quantify damage levels.
7. Laser beam uniformity is not addressed, which may affect the repeatability and accuracy of the experimental results.
8. Finite element modeling assumptions are overly simplified, such as treating all layers as isotropic, assuming constant thermal properties, and ignoring non-thermal effects.
9. There is no quantitative comparison between simulation results and experimental data. Claims of consistency are qualitative only.
10. Boundary conditions in the simulation are oversimplified. Assuming a constant ambient temperature of 298 K ignores possible heat accumulation and environmental variations.

Author Response

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Reviewer 4 Report

Comments and Suggestions for Authors

Article is overall properly structured and well written, and results can be of interest for scientists and engineers working in the topic. The article could still be improved, so   

my conclusion is that manuscript could be published in Photonics only after major revision.

Comments and suggestions:

1. Page 1, line 2: typo in the title, „t“ missing in the word detector.
2. Page 5, Theoretical model: The thermodynamic parameters of materials are given in Table 1. Optical parameters (absorptivity to the laser light β) should also be given, if they were used during calculations.
3. Page 5, Experiments: Type, manufacturer and model of the laser used should be given. Size of the laser spot on the targets surface must be given. Laser pulse energy (not just energy density) should also be given.
4. Page 6, Experiments: Model and manufacturer of energy meter should also be stated.
5. Results and Analysis, Page 6, line 182, Page 9, line 249: It would be very beneficial for this research if you could perform morphological measurements (for example profilometry or confocal microscopy) of the ablated area, which would give better understanding of the damage depth and shape.
6. Page 10, References: Adding few more references would be good; having only 20 references feels lacking.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Changes of the paper are appropriate, and it is suitable for publication in Photonics.