Pulse Duration Compression by Two-Stage Stimulated Brillouin Scattering and Stimulated Raman Scattering
, Shaowen Li 1, Sensen Li 1,3, Zhongwei Yang 1, Qiang Su 1, Yu Zhang 2, Bayanheshig 4, Yuanqin Xia 1, Yulei Wang 1 and Zhiwei Lu 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors presented a pulse duration compression technique combining stimulated Brillouin scattering and stimulated Raman scattering, and achieved an output pulse duration of 48.3 ps with an energy of 5.27 mJ. I have a few concerns over this work.
1. Why not the author measure the beam quality of the output laser instead of the beam profiles in Fig.6 and Fig.9? The demension of the beam profile can be affected by the propogation distance and the imaging system, so it is better to measure the beam quality.
2. What are the primary limit of further compressing the pulse duration? And how to further improve the efficiency?
3. The caption of Fig.3 is wrong, please correct.
Author Response
Dear Reviewer，
We would like to express our sincere appreciation to your warm work and thank you for this great opportunity for us to improve the manuscript " Pulse duration compression by two-stage stimulated Brillouin scattering and stimulated Raman scattering, ID: photonics-2782161".
We have carefully considered the comments from you, which helped us to improve the manuscript substantially. Each suggested revision and comment brought forward by the reviewers was accurately incorporated and considered. We revised the content of the manuscript according to the valuable suggestions from you. A response letter has been uploaded which provides a point-to-point response to your comments. Each revised content is highlighted in blue.
Once again, thank you very much for your consideration of our manuscript.
Wish you all the best!
Sincerely yours,
Xiaoyan Han, Zhaohong Liu, Shaowen Li, Sensen Li, Zhongwei Yang, Qiang Su, Yu Zhang, Bayanheshig, Yuanqin Xia, Yulei Wang, and Zhiwei Lu
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors experimentally demonstrate the possibility of generating laser pulses with energies of tens of millijoules and durations of less than 100 ps. The pump radiation is a Q-switched neodymium laser generating pulses with a duration of 7 ns. The physical mechanism providing this reduction in pulse duration is a combination of stimulated Brillouin scattering and stimulated Raman scattering. The topic is interesting, and I have some questions to discuss with the authors:
Point 1. To increase the second Stokes generation threshold, the authors use a decrease in the pump pulse duration. Perhaps the threshold can be increased simply by using a light filter or light filters that block the radiation of the second Stokes?
Point 2. The inset in Fig. 5b shows the change in the Stokes pulse with time. Why is only the area with positive signal values considered as the pulse duration? In this case, a careful analysis of the physical processes that determine the observed pulse shape (both positive and negative values) is necessary, and only on this basis it is necessary to provide correct estimates of the pulse duration. The same is for Fig.7b.
Point 3. Fig.3. The caption is unclear.
Point 4. Fig.6. In fact, this drawing is just color pictures. It is necessary to indicate in which section of the beam the measurements were made, and provide the values of coordinates and intensity along all three coordinate axes. Figures (a) and (b) are both three-coordinate graphs, so it is necessary to indicate the spatial axes, as well as the correspondence between color and radiation intensity.
Point 5. What is indicated as AM in Fig.2?
Point 6. Fig. 1 contains practically no information due to the relativity of the quantities plotted along the vertical axes. It can be removed without compromising understanding. In addition, areas of negative time and intensity values can be misleading.
Point 7. Equation (1) is not shown in reference [22]. Its origin needs to be explained.
Point 8. The same applies to equation (2). In addition, in most literature the permittivity of a free space is denoted as εo. In the article, the authors use the notation δo for this quantity, and εo denotes the amplitude of the light wave. Perhaps it would be more appropriate to use generally accepted notations? It is also necessary to clearly indicate whether the “amplitude of fundamental frequency light” refers to the magnitude of the electric field or to the intensity of the radiation.
Point 9. Equation (5) does not match the text.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer，
We would like to express our sincere appreciation to your warm work and thank you for this great opportunity for us to improve the manuscript " Pulse duration compression by two-stage stimulated Brillouin scattering and stimulated Raman scattering, ID: photonics-2782161".
We have carefully considered the comments from you, which helped us to improve the manuscript substantially. Each suggested revision and comment brought forward by the reviewers was accurately incorporated and considered. We revised the content of the manuscript according to the valuable suggestions from you. A response letter has been uploaded which provides a point-to-point response to your comments. Each revised content is highlighted in blue.
Once again, thank you very much for your consideration of our manuscript.
Wish you all the best!
Sincerely yours,
Xiaoyan Han, Zhaohong Liu, Shaowen Li, Sensen Li, Zhongwei Yang, Qiang Su, Yu Zhang, Bayanheshig, Yuanqin Xia, Yulei Wang, and Zhiwei Lu
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsIn this manuscript, Han et al. reported a laser pulse compression method which can compress a 7.4-ns pulse to 48.3ps. This method consists of two stages. The first stage utilises stimulated Brillouin scattering (SBS) effect, and compresses the pulse from 7.4ns to 580ps with high energy efficiency. The second stage further compresses the pulse from 580ps to 48.3ps using stimulated Raman scattering (SRS) effect. This method combines the merits of high energy efficiency from SBS and large bandwidth from SRS, and achieves a total compression ratio of about 150.
This work is interesting to the laser technology community. I have the following questions regarding to this manuscript:
1. In the abstract, the authors mentioned that "energy efficiency is up to 21.84%". From the context, this efficiency should be of the whole system. However, 21.84% seems to be of the SRS stage. Similarly, in the conclusion part, the sentence "The technology of combining SBS and SRS system achieved a total energy output of 5.27 mJ at a total input energy of 24.13 mJ , with an energy efficiency up to 21.84% ..." describes the the system combining the SBS and SRS stages. Therefore, the input energy should be of the SBS system, and the energy efficiency should be the whole system's.
2. In section 3, it is mentioned that "a compact double cell structure is used to output 28.6 mJ of Stokes with a pulse duration of 580 ps at a pump energy of 35 mJ". In section 4, "At the pump energy of 35.2 mJ , the output Stokes pulse duration is 580 ps , and the corresponding output energy is 26.8 mJ". Is there an inconsistancy?
3. The caption of Figure 3 is missing.
4. The output durations for both the SRS generator and amplifier are above 60ps, while the SRS compression output is 48ps. The authors can give an explanation on this point in the manuscript.
The manuscript is poorly written. And many letters in the formulae are not chosen according to convention, which makes them difficult to understand. For example, the use of \epsilon_{0}.
Author Response
Dear Reviewer，
We would like to express our sincere appreciation to your warm work and thank you for this great opportunity for us to improve the manuscript " Pulse duration compression by two-stage stimulated Brillouin scattering and stimulated Raman scattering, ID: photonics-2782161".
We have carefully considered the comments from you, which helped us to improve the manuscript substantially. Each suggested revision and comment brought forward by the reviewers was accurately incorporated and considered. We revised the content of the manuscript according to the valuable suggestions from you. A response letter has been uploaded which provides a point-to-point response to your comments. Each revised content is highlighted in blue.
Once again, thank you very much for your consideration of our manuscript.
Wish you all the best!
Sincerely yours,
Xiaoyan Han, Zhaohong Liu, Shaowen Li, Sensen Li, Zhongwei Yang, Qiang Su, Yu Zhang, Bayanheshig, Yuanqin Xia, Yulei Wang, and Zhiwei Lu
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe reviewer believes that after the text has been corrected by the authors, the article can be published in its presented form.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors responded to my comments. This work can be published.
