Research on the Terahertz Modulation Performance of VO₂ Thin Films with Surface Plasmon Polaritons Structure

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review of “Research on the Terahertz Modulation Performance of VO₂ Thin Films with SPP Structure”

Summary
The manuscript reports on the fabrication of VO₂ thin films on silicon substrates, their integration with surface-plasmon-polariton (SPP) metallic structures, and the study of terahertz (THz) modulation performance under various optical excitations (continuous-wave and femtosecond lasers). The authors combine experimental THz-TDS measurements with numerical simulations to demonstrate dual-function devices capable of both modulation and frequency-selective filtering.

1. Line 1–15 (Abstract): It is not entirely clear what the novel element of this work is relative to existing VO₂-based THz modulators. Several groups have reported femtosecond-driven phase transitions in VO₂ for THz control (e.g. ref. 7–11). Please explicitly state what gap your work fills: is it the integration with SPP hole/block arrays? The dual-function nature? Quantify how your modulation depth or speed compares to prior art.
2. More background information on vanadium oxide would have been useful in the introduction. This would have greatly increased the number of potential readers.

1. Consistency in Materials Description.  Section 3.1 (Line 115): You introduce “W-VO₂” nanoparticles and discuss tungsten doping, yet the title and most of the paper focus on pure VO₂ films. Is tungsten-doped VO₂ used in all optical experiments? If so, please clarify in the Methods (Section 2.1) and adjust the title/abstract accordingly. If not, remove or relocate the W-VO₂ discussion to a separate study.
2. Lines 103–112: The configuration of the THz-TDS setup is briefly described, but key parameters are missing:  Spot size and uniformity of the optical pump on the sample (you mention 0.4 mm in Sec 3.2 but not earlier). Number of repeats per measurement and standard deviations/error bars for modulation depth. Calibration procedure for extracting complex conductivity (Eq. 4).  Without these details, it is hard to judge the reliability and repeatability of your results.
3. Reference to Recent Literature. You cite two 2024 review articles on VO₂ films (refs 1–2) and several 2025 device studies (refs 7–12), which is good. However, a number of relevant experimental reports from 2023 (e.g. on ultrafast THz switching in VO₂ heterostructures) are missing. Please broaden your literature survey to include 2023 works such as Z. Li et al., Adv. Photonics 2023, on VO₂ metasurfaces, and discuss how your design compares.
4. Figures 7, 9 (Time- and frequency-domain THz pulses): The axes are unlabeled (no units on amplitude). Please add clear axis labels, include error bars, and—for spectral plots—indicate the signal-to-noise ratio.  Figure 11 (Conductivity): The real part of σ̃ reaches ~10⁶ S/m at high pump; please overlay typical metal conductivity ranges (e.g. gold at THz) for context.
5. Section 3.5 (Lines 264–276): You observe that DLSP resonance is more strongly disrupted by the VO₂ phase change than SP resonance. This is intriguing. Please deepen the discussion: Why might the field confinement of DLSP modes make them more sensitive to the dielectric change? Could this be exploited to design even sharper filters? A more quantitative analysis (e.g. simulated quality factors before/after) would strengthen the manuscript.
6. To what extent are the studied films free from point defects? More precisely, from vacancies in the anion and cation sublattices? It is known that they are always present and can be in several charge states both in binary and more complex oxides. See, reviews:

Popov, A. I., Kotomin, E. A., & Maier, J. (2010). Basic properties of the F-type centers in halides, oxides and perovskites. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 268(19), 3084-3089.

Borgekov, D. B., Zhumazhanova, A. T., Kaliyekperova, K. B., Azambayev, S. B., Kozlovskiy, A. L., Konuhova, M., ... & Shlimas, D. I. (2024). The effect of oxygen vacancies on the optical and thermophysical properties of (1-x) Si3N4–xAl2O3 ceramics. Optical Materials, 157, 116056.

Strand, J., Chulkov, S. K., Watkins, M. B., & Shluger, A. L. (2019). First principles calculations of optical properties for oxygen vacancies in binary metal oxides. The Journal of Chemical Physics, 150(4).

9. Nomenclature Consistency. The manuscript alternates between “VO2”, “VOx”, and “vanadium oxide”. Please standardize to “VO₂” (with subscript) everywhere.
10. Simulation Details. Section 3.5: In the electric-field simulations, the VO₂ conductivity jumps from 10² S/m to 10⁴ S/m—these values are cited as from “Morin’s measurement (1959)”. More modern measurements (e.g. ref 14, Quackenbush et al. 2013) report different numbers; please justify your choice.

 

Author Response

Comments 1: Line 1–15 (Abstract): It is not entirely clear what the novel element of this work is relative to existing VO₂-based THz modulators. Several groups have reported femtosecond-driven phase transitions in VO₂ for THz control (e.g. ref. 7–11). Please explicitly state what gap your work fills: is it the integration with SPP hole/block arrays? The dual-function nature? Quantify how your modulation depth or speed compares to prior art.

Response 1: Our innovation lies in developing a VO₂ thin film with an SPP structure, which possesses both modulation and filtering functions. In the Abstract section (page 1), I have quantitatively described the performance of this experimental result: "The experiment proves that the VO2 film with an SPP structure, under light excitation, has a transmission rate dropping sharply from 32% to 1%; the resistivity changes by more than six orders of magnitude, and the modulation effect is remarkable."

Comments 2: More background information on vanadium oxide would have been useful in the introduction. This would have greatly increased the number of potential readers.

Response 2: I agree with your suggestion. In the introductory part of the paper (on page 1), I have added the current research status of vanadium oxide in recent years to enhance the reliability and comprehensiveness of the paper.

Comments 3: Consistency in Materials Description.  Section 3.1 (Line 115): You introduce “W-VO₂” nanoparticles and discuss tungsten doping, yet the title and most of the paper focus on pure VO₂ films. Is tungsten-doped VO₂ used in all optical experiments? If so, please clarify in the Methods (Section 2.1) and adjust the title/abstract accordingly. If not, remove or relocate the W-VO₂ discussion to a separate study.

Response 3: The materials described in the text are all VO₂, without any other doping. Therefore, all the descriptions of the W element in the text have been deleted.

Comments 4: Lines 103–112: The configuration of the THz-TDS setup is briefly described, but key parameters are missing:  Spot size and uniformity of the optical pump on the sample (you mention 0.4 mm in Sec 3.2 but not earlier). Number of repeats per measurement and standard deviations/error bars for modulation depth. Calibration procedure for extracting complex conductivity (Eq. 4).  Without these details, it is hard to judge the reliability and repeatability of your results.

Response 4: In Section 2.3 of the text (on page 4), the optical path structure, device functions, and optical parameters of THz-TDS are described in detail. At the same time, the reason for setting the spot diameter to 0.4mm is explained. This system uses a titanium-sapphire femtosecond laser as the pump source, with a central working wavelength of 800nm, a repetition frequency of 100MHz, a pulse width of 50fs, and an average power of 520mW. The generation and detection methods of terahertz radiation are micro-optical rectification and electro-optic sampling, and the nonlinear crystals all use zinc telluride (ZnTe). The effective spectral range of the system is 0.3 to 2.5THz. The spot size on the VO₂ film surface is controlled by the lens system composed of lenses L1 and L2. Through multiple experiments and optimizations, it was found that the best effect is achieved when the spot diameter is 0.4mm.

Comments 5: Reference to Recent Literature. You cite two 2024 review articles on VO₂ films (refs 1–2) and several 2025 device studies (refs 7–12), which is good. However, a number of relevant experimental reports from 2023 (e.g. on ultrafast THz switching in VO₂ heterostructures) are missing. Please broaden your literature survey to include 2023 works such as Z. Li et al., Adv. Photonics 2023, on VO₂ metasurfaces, and discuss how your design compares.

Response 5: Thank you for your suggestion. I have referred to the recent literature. For example:

1. Zhang, Y.; Li, K.; Zhao, H. Intense terahertz radiation: generation and application. Frontiers of Optoelectronics 2021, 14, 4–36. 
2. Buldt, J.; Stark, H.; Müller, M.; Grebing, C.; Jauregui, C.; Limpert, J. Gas-plasma-based generation of broadband terahertz radiation with 640 mW average power. Optics Letters 2021, 46, 5256–5259. 

3. Carnio, B.N.; Moutanabbir, O.; Elezzabi, A.Y. Nonlinear photonic waveguides: a versatile platform for terahertz radiation generation (a review). Laser & Photonics Reviews 2023, 17, 2200138. 

4. Choi, W.J.; Armstrong, M.R.; Yoo, J.H.; Lee, T. Toward high-power terahertz radiation sources based on ultrafast lasers. Journal of Materials Chemistry C 2024, 12, 9002–9011. 

5. Jin, L.; Song, J.; Chen, L.; Yao, X.; Zhao, H.; Cheng, Q. VO2-based switchable thermal emitters using magnetic polaritons. Journal of Quantitative Spectroscopy and Radiative Transfer 2024, 317, 108937. 

6. Johnson, A.S.; Perez-Salinas, D.; Siddiqui, K.M.; Kim, S.; Choi, S.; Volckaert, K.; Majchrzak, P.E.; Ulstrup, S.; Agarwal, N.; Hallman, K.; et al. Ultrafast X-ray imaging of the light-induced phase transition in VO2. Nature Physics 2023, 19, 215–220. 

7. Wang, Z.; Ji, X.; Dong, N.; Chen, C.; Yan, Z.; Cao, X.; Wang, J. Femtosecond laser-induced phase transition in VO2 films. Optics Express 2022, 30, 47421–47429. 

8. Hwang, I.H.; Jin, Z.; Park, C.I.; Sun, C.J.; Brewe, D.L.; Han, S.W. Electrical and structural properties of VO2 in an electric field.Current Applied Physics 2021, 30, 77–84.

Comments 6: Figures 7, 9 (Time- and frequency-domain THz pulses): The axes are unlabeled (no units on amplitude). Please add clear axis labels, include error bars, and—for spectral plots—indicate the signal-to-noise ratio.  Figure 11 (Conductivity): The real part of σ̃ reaches ~10⁶ S/m at high pump; please overlay typical metal conductivity ranges (e.g. gold at THz) for context.

Response 6: For Figures 7 and 9: The amplitude is expressed in arbitrary units (a.u.), aiming to highlight the relative changes caused by light excitation, as the absolute terahertz field strength is not the focus of this modulation study. This approach is common in terahertz time-domain spectroscopy analysis (THz-TDS) and is used to compare spectral characteristics under different excitation conditions. Each measurement was repeated three times to verify repeatability. The curves shown represent representative data.
For Figure 11: The electrical conductivity of conventional conductor metals does not change significantly under terahertz action, so only the range of common metal electrical conductivities is given in the text, i.e., >10⁶ S/m (line 265).

Comments 7: Section 3.5 (Lines 264–276): You observe that DLSP resonance is more strongly disrupted by the VO₂ phase change than SP resonance. This is intriguing. Please deepen the discussion: Why might the field confinement of DLSP modes make them more sensitive to the dielectric change? Could this be exploited to design even sharper filters? A more quantitative analysis (e.g. simulated quality factors before/after) would strengthen the manuscript.

Response 7: The SP mode and DLSP mode are achieved by using a metal-semiconductor material array. Currently, simulation has been conducted for their mechanism research, but no effective experimental methods have been found to verify our hypotheses. This is also one of the future research directions.

Comments 8: To what extent are the studied films free from point defects? More precisely, from vacancies in the anion and cation sublattices? It is known that they are always present and can be in several charge states both in binary and more complex oxides. See, reviews:

Popov, A. I., Kotomin, E. A., & Maier, J. (2010). Basic properties of the F-type centers in halides, oxides and perovskites. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 268(19), 3084-3089.

Borgekov, D. B., Zhumazhanova, A. T., Kaliyekperova, K. B., Azambayev, S. B., Kozlovskiy, A. L., Konuhova, M., ... & Shlimas, D. I. (2024). The effect of oxygen vacancies on the optical and thermophysical properties of (1-x) Si3N4–xAl2O3 ceramics. Optical Materials, 157, 116056.

Strand, J., Chulkov, S. K., Watkins, M. B., & Shluger, A. L. (2019). First principles calculations of optical properties for oxygen vacancies in binary metal oxides. The Journal of Chemical Physics, 150(4).

Response 8: For the metal oxide type films, oxygen vacancies and metal impurities do have significant effects on the material properties. However, this paper mainly discusses the optical properties of the combination of VO₂ materials and SPP structures. Due to space limitations, the influence of defects cannot be fully explored. Inspired by your suggestion, in the future, a separate article can be written about the impact of defects on the materials.

Comments 9: Nomenclature Consistency. The manuscript alternates between “VO2”, “VOx”, and “vanadium oxide”. Please standardize to “VO₂” (with subscript) everywhere.

Response 9: I have standardized all the positions in the text to VO₂.

Comments 10: Simulation Details. Section 3.5: In the electric-field simulations, the VO₂ conductivity jumps from 10² S/m to 10⁴ S/m—these values are cited as from “Morin’s measurement (1959)”. More modern measurements (e.g. ref 14, Quackenbush et al. 2013) report different numbers; please justify your choice.

Response 10: We used the most recent data of a conductivity variation range of 10² - 10⁴ S/m as the simulation parameters (from Liang, J.;  ) Lou, Q.; Wu, W.; Wang, K.; Xuan, C. NO2 gas sensing performance of a VO2 (B) ultrathin vertical nanosheet array: experimental and DFT investigation. ACS Applied Materials & Interfaces 2021, 13, 31968—31977. 418), This study focused on the bulk-equivalent-thickness silicon-based films, whose carrier transport mechanism is more similar to the bulk material behavior described by Liang.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is dedicated to SPP in the THz structures containing VO2 components. It contains the 
experimental results, which can be interesting for reader. 
The paper can be recommended for publication but needs some revision.

The below listed issues should be addressed in the revised manuscript:

1) THz (meta-)structures with VO2 components are often considered as a well saturated field 
of research, so the novelty and impact of this work should be clearer explained for wide reader
2) for the sake of generality, I suggest to cite and briefly discuss some papers, which 
may demonstrate the potential of metastructures with VO2 components in the different parts of electromagnetic spectrum, e.g., 
Kepic, P., et al. ACS Photonics, vol. 8, no. 4, pp. 1048-1057 (2021); Serebryannikov, A. E., 
et al. Optical Materials Express, vol. 12, no. 12, pp. 4594-4605 (2022); Inokuma, et al. Applied Physics Letters, vol. 125, no. 8, 081703 (2024); Tripathi, A., et al. ACS Photonics, vol. 8, 
no. 4, pp. 1206-1213 (2021)
3) Line 62-63: why "the loss of SPP in the terahertz band is very low"? what kind of SPP is 
meant here? how low it is in comparison with other kinds/structures/frequency ranges? 
4) Line 53: the correct name seems to be Ebbesen
5) explain for wide reader what means W-VO2; why W?
6) explain what is a reason of considering two types of design (page 3); what are the main 
differences between them in terms of fabrication and functionality?
7) Line 155: is such a high temperature like 400C is inevitable for your purposes? 
8) how is the introduced model of conductivity consistent with the earlier suggested models? 
(page 9) 
9) what kind of information you can obtain due to the use of time-domain waveforms, which cannot be obtained by using monochromatic waves? more generally, what is a reason of using time-domain waveforms in your work?
10) Lines 254-255: please, explain why it may occur

Author Response

Comments 1: THz (meta-)structures with VO2 components are often considered as a well saturated field 
of research, so the novelty and impact of this work should be clearer explained for wide reader

Response 1: I have added a description of the innovation of the paper in the abstract, namely "By applying the SPP structure to the VO₂ material, the material can simultaneously possess modulation and filtering functions, enhancing the optical performance of the material in the terahertz band". And I have also quantitatively described the performance of this experimental result.

Comments 2: for the sake of generality, I suggest to cite and briefly discuss some papers, which 
may demonstrate the potential of metastructures with VO2 components in the different parts of electromagnetic spectrum, e.g., 
Kepic, P., et al. ACS Photonics, vol. 8, no. 4, pp. 1048-1057 (2021); Serebryannikov, A. E., 
et al. Optical Materials Express, vol. 12, no. 12, pp. 4594-4605 (2022); Inokuma, et al. Applied Physics Letters, vol. 125, no. 8, 081703 (2024); Tripathi, A., et al. ACS Photonics, vol. 8, 
no. 4, pp. 1206-1213 (2021)

Response 2: I agree with your suggestion. In the introduction part of the paper, I have added the current research status of vanadium oxide in recent years to enhance the reliability and comprehensiveness of the paper. I have also cited some references, such as:

1. Zhang, Y.; Li, K.; Zhao, H. Intense terahertz radiation: generation and application. Frontiers of Optoelectronics 2021, 14, 4–36. 
2. Buldt, J.; Stark, H.; Müller, M.; Grebing, C.; Jauregui, C.; Limpert, J. Gas-plasma-based generation of broadband terahertz radiation with 640 mW average power. Optics Letters 2021, 46, 5256–5259. 

3. Carnio, B.N.; Moutanabbir, O.; Elezzabi, A.Y. Nonlinear photonic waveguides: a versatile platform for terahertz radiation generation (a review). Laser & Photonics Reviews 2023, 17, 2200138. 

4. Choi, W.J.; Armstrong, M.R.; Yoo, J.H.; Lee, T. Toward high-power terahertz radiation sources based on ultrafast lasers. Journal of Materials Chemistry C 2024, 12, 9002–9011. 

5. Jin, L.; Song, J.; Chen, L.; Yao, X.; Zhao, H.; Cheng, Q. VO2-based switchable thermal emitters using magnetic polaritons. Journal of Quantitative Spectroscopy and Radiative Transfer 2024, 317, 108937. 

6. Johnson, A.S.; Perez-Salinas, D.; Siddiqui, K.M.; Kim, S.; Choi, S.; Volckaert, K.; Majchrzak, P.E.; Ulstrup, S.; Agarwal, N.; Hallman, K.; et al. Ultrafast X-ray imaging of the light-induced phase transition in VO2. Nature Physics 2023, 19, 215–220. 

7. Wang, Z.; Ji, X.; Dong, N.; Chen, C.; Yan, Z.; Cao, X.; Wang, J. Femtosecond laser-induced phase transition in VO2 films. Optics Express 2022, 30, 47421–47429. 

8. Hwang, I.H.; Jin, Z.; Park, C.I.; Sun, C.J.; Brewe, D.L.; Han, S.W. Electrical and structural properties of VO2 in an electric field.Current Applied Physics 2021, 30, 77–84.

Comments 3: Line 62-63: why "the loss of SPP in the terahertz band is very low"? what kind of SPP is 
meant here? how low it is in comparison with other kinds/structures/frequency ranges? 

Response 3: The SPP structure refers to "Surface Plasmon Polariton". In this paper, a metal repetitive structure is utilized to achieve it. Different metals and different structural forms result in different loss conditions. In this case, the transmittance of a pure VO₂ film without the SPP structure is 32%, while the transmittance of a VO₂ film with the SPP structure is approximately 60%.

Comments 4: Line 53: the correct name seems to be Ebbesen

Response 4: It has been corrected. Thank you for the reminder.

Comments 5: explain for wide reader what means W-VO2; why W?

Response 5: Many VO₂ films adopt the method of doping tungsten to enhance their performance. Our research group has also explored similar approaches. However, this paper does not cover the content of tungsten doping. Therefore, the part related to tungsten has been deleted.

Comments 6: explain what is a reason of considering two types of design (page 3); what are the main 
differences between them in terms of fabrication and functionality?

Response 6: The adoption of these two designs is mainly due to two reasons. Firstly, to compare the effects of the SPP structure and the DLSP (local electronic oscillation) form on terahertz waves. Secondly, these two structures are convenient to implement in the process of fabrication and have practical value.

Comments 7: Line 155: is such a high temperature like 400C is inevitable for your purposes? 

Response 7: 400℃ refers to the annealing temperature of the VO₂ material. This is based on the results of a large number of process experiments conducted by our research group in the past. The typical annealing temperature ranges from 300 to 600℃. Depending on the specific application of the material, an appropriate annealing temperature should be selected within this range.

Comments 8: how is the introduced model of conductivity consistent with the earlier suggested models? 
(page 9) 

Response 8: The model introduced on page 9 focuses on inferring the changes in material's electrical conductivity from optical tests. The previously proposed model was based on the data obtained from electrical tests of the material. The consistency between the two models is reflected in the fact that the amplitude of the electrical conductivity changes before and after the phase transition of vanadium dioxide is consistent in the analysis. This amplitude of electrical conductivity change is the focus of this article.

Comments 9:what kind of information you can obtain due to the use of time-domain waveforms, which cannot be obtained by using monochromatic waves? more generally, what is a reason of using time-domain waveforms in your work?

Response 9: The time-domain waveform is mainly used to compare the changes in optical transmittance of VO₂ materials before and after phase transformation. This is also one of the characteristics of the THz-TDS (Terahertz Time-Domain Spectroscopy) system, which can simultaneously obtain both time-domain and frequency-domain information, serving as an auxiliary explanation for the spectrum.

Comments 10:Lines 254-255: please, explain why it may occur

Response 10: The VO₂ film is a polycrystalline material. Different crystal grains can also form a similar SPP structure, thereby disrupting the original structural characteristics of the metal SPP and resulting in additional losses at certain frequencies.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Regarding my previous comment 8, the authors rightly and accurately noted that "For the metal oxide type films, oxygen vacancies and metal impurities do have significant effects on the material properties. However, this paper mainly discusses the optical properties of the combination of VO2 materials and SPP structures. Due to space limitations, the influence of defects cannot be fully explored. Inspired by your suggestion, in the future, a separate article can be written about the impact of defects on the materials."   

However, I still believe that 5-8 lines briefly describing the situation with defects will be absolutely useful for readers, especially for beginners.

Author Response

Comments 1：

Regarding my previous comment 8, the authors rightly and accurately noted that "For the metal oxide type films, oxygen vacancies and metal impurities do have significant effects on the material properties. However, this paper mainly discusses the optical properties of the combination of VO2 materials and SPP structures. Due to space limitations, the influence of defects cannot be fully explored. Inspired by your suggestion, in the future, a separate article can be written about the impact of defects on the materials."   

However, I still believe that 5-8 lines briefly describing the situation with defects will be absolutely useful for readers, especially for beginners.

Response 1 ：Thank you for your valuable comments on this article. We have incorporated your suggestions by providing a brief description of the impact of defects in the text (see revised version, lines 174-183, highlighted in red):

  "For the polycrystalline VO₂ thin films, their electrical properties are not only related to the grain boundaries of the polycrystalline films, but also to the oxygen vacancies in the films. The existence of grain boundaries is equivalent to introducing impurity energy levels in the band gap, reducing the activation energy; oxygen vacancies introduce acceptor energy levels in the band gap, also leading to a decrease in the activation energy. Both types of defects will cause a decline in the phase transition performance of the VO₂ thin films. Additionally, oxygen vacancies will introduce excess electrons in the films, reducing the optical transmittance of the VO₂ thin films. Therefore, appropriate preparation process conditions are conducive to obtaining controllable grain distribution and oxygen vacancyconcentration, thereby obtaining the optimal VO₂ thin film material for phase transition."

Your suggestions are very helpful in improving the readability of the paper. In the future, we will conduct more in-depth research on the impact of these defects.

Round 3

Reviewer 1 Report

Comments and Suggestions for Authors

Please see below:

Lines 174-183.  

1. Each sentence here must be supported by an appropriate reference !!!
2. Keep in mind that oxygen vacancies in oxides can be in three charge states and I look forward to a short but specific discussion about which vacancies are in your case and why

Popov, A. I., Kotomin, E. A., & Maier, J. (2010). Basic properties of the F-type centers in halides, oxides and perovskites. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 268(19), 3084-3089.

Strand, J., Chulkov, S. K., Watkins, M. B., & Shluger, A. L. (2019). First principles calculations of optical properties for oxygen vacancies in binary metal oxides. The Journal of Chemical Physics, 150(4).

This is a strict condition to accept your manuscript !!!

Author Response

Comments 1：

Please see below:

Lines 174-183.  

1. Each sentence here must be supported by an appropriate reference !!!
2. Keep in mind that oxygen vacancies in oxides can be in three charge states and I look forward to a short but specific discussion about which vacancies are in your case and why

Popov, A. I., Kotomin, E. A., & Maier, J. (2010). Basic properties of the F-type centers in halides, oxides and perovskites. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 268(19), 3084-3089.

Strand, J., Chulkov, S. K., Watkins, M. B., & Shluger, A. L. (2019). First principles calculations of optical properties for oxygen vacancies in binary metal oxides. The Journal of Chemical Physics, 150(4).

This is a strict condition to accept your manuscript !!!

request 1：We sincerely thank the reviewers for their insightful and profound suggestions regarding the oxygen vacancy state in the VO₂ film. In response to the issues raised, we have carefully revised the paper to strengthen the theoretical basis of our discussion. We are extremely grateful for the opportunity to improve our paper through these valuable suggestions.“The three states of oxygen vacancies in the VO₂ thin film are V_o ⁰(524.1 eV), V_o ⁺¹(522.8 eV), and V_o⁺² (519.9 eV). Among them, as the V³⁺ ions in the material gradually increase, the positive divalent oxygen vacancies gradually decrease, which conforms to the change trend of formula (1). ”（lines 173-176）