Bi-frequency operation in a membrane external-cavity surface-emitting laser

Jake Daykin; Jonathan R. C. Woods; Roman Bek; Michael Jetter; Peter Michler; Ben Mills; Peter Horak; James S. Wilkinson; Vasilis Apostolopoulos

doi:10.1371/journal.pone.0289223

Peer Review History

Original SubmissionMay 26, 2023
18 Jun 2023 Decision Letter - Xuejian Wu, Editor PONE-D-23-16239Bi-frequency operation in a membrane external-cavity surface-emitting laserPLOS ONE Dear Dr. Daykin, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Aug 02 2023 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. 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The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. We note that you have stated that you will provide repository information for your data at acceptance. Should your manuscript be accepted for publication, we will hold it until you provide the relevant accession numbers or DOIs necessary to access your data. If you wish to make changes to your Data Availability statement, please describe these changes in your cover letter and we will update your Data Availability statement to reflect the information you provide. 3. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: Please see the attached file. Reviewer #2: In this article, the authors report continuous wave bi-frequency operation in a membrane external-cavity surface-emitting laser (MECSEL). By controlling spatially specific loss on certain transverse cavity modes, the authors successfully operated the laser on two Hermite-Gaussian spatial modes simultaneously. The experimental results support their findings, showcasing bi-frequency operation across different parameters. The clear description and substantial results demonstrate the quality and significance of the research. I would like to recommend the manuscript to be accepted for publication. I have a couple of minor comments: 1.) Could the author clarify more about how does this work differs from previous work? Other than using a ablation pattern, are there any other methods for bi-frequency operation? It would be more informative to brief talk about this in the introduction. 2.) What’s the beam radii of even higher order modes (other than HG00 and HG11)? It would be helpful to add this information in section 2.3. Reviewer #3: The paper titled "Bi-frequency operation in a membrane external-cavity surface-emitting laser " by Jake Daykin et al demonstrates the continuous wave bi-frequency operation in a membrane external-cavity surface-emitting laser. By introducing spatially specific loss to the intra-cavity high reflectivity mirror with laser ablated mirror masks, the laser simultaneously operates on two Hermite-Gaussian spatial modes. The bi-frequency operation is demonstrated across different pump powers and sizes of spatial loss features, with a wavelength separation of approximately 5nm centered at 1005 nm. The paper is properly structured and well written. The experiments in section 2 and 3 are well designed and convincing. The idea of utilizing spatially dependent loss within the MECSEL cavity to control transverse cavity modes and facilitate the oscillation of two specific spatial modes is new to the field. Therefore the paper in my opinion certainly should be considered for publication in PLOS ONE. There is one minor issue to address: On page 1, line 7, please write out the full expressions of VECSEL on first use. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No Reviewer #3: Yes: Weicheng Zhong ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. Attachments Attachment Submitted filename: Review PONE-D-23-16239.pdf https://doi.org/10.1371/journal.pone.0289223.r001
Revision 1
10 Jul 2023 Author Response Dear Editor, Thank you for your latest correspondence regarding the peer review decision for manuscript PONE-D-23-16239, titled “Bi-frequency operation in a membrane external-cavity surface-emitting laser” First of all, I would like to thank the reviewers for their time in reviewing our manuscript which helped us to improve the quality of the manuscript. In response to the feedback from the reviewers, we have taken the time to improve the manuscript and would like to take the opportunity to respond to each of the comments presented by the reviewers. Reviewer 1: In this paper, the authors demonstrated an optically pumped bi-frequency MECSEL. One of the cavity mirrors is laser ablated to introduce a transverse-mode-dependent loss, making it possible for two transverse modes to lase simultaneously with similar output power. The manuscript introduces details on the laser structure including the ablated mirror, cavity, gain medium, and pump laser. Operations under various pump power and different ablated masks are experimentally studied. The results show promising bi-frequency operations with tuning capabilities. I would like to recommend the manuscript be published after addressing a few questions below: 1. The acronym “VECSEL” first appears in line 7, while the full term “Vertical External-Cavity Surface-Emitting Laser” appears later in line 14. Please make sure the acronym is defined at the first appearance. 2. In line 61, the masks are described as “with ablated central regions”. However, the actual masks seem to have unablated central regions. Can the authors clarify this? 3. In line 132, the authors mentioned Fig. 5 has a 300-mW increment of pump power. The pump power range in Fig. 5 plots is about 2.5 ~ 4.0 W, so there should be only 5 or 6 discrete pump power values. However, some plots in Fig. 5 show more than 6 different spectrum sections across the pump power range, so it seems the increment is less than 300 mW. Can the authors clarify this? 4. In Fig. 5, is the colormap in log scale or linear scale? Some plots seem to have a higher noise floor at some pump power values (for example, the 50 um mask plot at about 2.5 W pump power). What is the reason for this? We thank the reviewer for their thorough comments and have addressed them in the following ways: Vertical External-Cavity Surface-Emitting Lasers defined on line 7 instead of line 14/15. Corrected typo of “ablated” to “unablated” on line 68. Corrected typo on line 150. Power increments are 60mW, not 300mW. The caption for Figure 5 has been altered to include the following: “The colour map representing the intensity of the spectra is logarithmic, and the noise floor between data sets differs due to the auto-zeroing of the optical spectrum analyser.” Reviewer 2: In this article, the authors report continuous wave bi-frequency operation in a membrane external-cavity surface-emitting laser (MECSEL). By controlling spatially specific loss on certain transverse cavity modes, the authors successfully operated the laser on two Hermite-Gaussian spatial modes simultaneously. The experimental results support their findings, showcasing bi-frequency operation across different parameters. The clear description and substantial results demonstrate the quality and significance of the research. I would like to recommend the manuscript to be accepted for publication. I have a couple of minor comments: 1.) Could the author clarify more about how does this work differs from previous work? Other than using a ablation pattern, are there any other methods for bi-frequency operation? It would be more informative to brief talk about this in the introduction. 2.) What’s the beam radii of even higher order modes (other than HG00 and HG11)? It would be helpful to add this information in section 2.3. We would like to thank the reviewer, and provide the following responses to their comments: A summary of the mechanisms used for creating a bi-frequency output is described in the second paragraph of the introduction, they include ablation of cavity mirrors, metalisation of the gain sample, birefringent filters in the cavity. The work described in this manuscript differs from previous work as we have implemented bi-frequency operation on the MECSEL Laser platform. The bi-frequency MECSEL presented is, to our knowledge, the first demonstration of a MECSEL operating on two frequencies simultaneously. Moving this technology to a MECSEL from the traditionally used VECSEL gives many opportunities as explained in the introduction and conclusions. MECSELs because of the removal of the intracavity DBR have the following advantages: faster to grow, better thermal management, greater wavelength selectability. We have altered the introduction of the paper to better highlight the previous work of generating bi-frequency operation in the VECSEL platform and explain the difference in our work. The radius (Rn,m) of a higher order mode is given by: R_(n,m)=R_00 √(1+n+m).Where R00 is the radius of the fundamental mode. We agree with the reviewer’s comment and have altered Section 2.3 to include the above relation and we have included a clarification that the HG 00, 11, 33, 55 etc modes would be able to operate within the mask design. However, modes higher order than the 11 will be suppressed by diffraction losses and by choice of cavity parameters. Reviewer 3: The paper titled "Bi-frequency operation in a membrane external-cavity surface-emitting laser " by Jake Daykin et al demonstrates the continuous wave bi-frequency operation in a membrane external-cavity surface-emitting laser. By introducing spatially specific loss to the intra-cavity high reflectivity mirror with laser ablated mirror masks, the laser simultaneously operates on two Hermite-Gaussian spatial modes. The bi-frequency operation is demonstrated across different pump powers and sizes of spatial loss features, with a wavelength separation of approximately 5nm centered at 1005 nm. The paper is properly structured and well written. The experiments in section 2 and 3 are well designed and convincing. The idea of utilizing spatially dependent loss within the MECSEL cavity to control transverse cavity modes and facilitate the oscillation of two specific spatial modes is new to the field. Therefore the paper in my opinion certainly should be considered for publication in PLOS ONE. There is one minor issue to address: On page 1, line 7, please write out the full expressions of VECSEL on first use. We thank the reviewer for their time and recommendation, and have addressed their raised issue: Vertical External-Cavity Surface-Emitting Lasers defined on line 7 instead of line 14/15 We thank the reviewers that helped us to improve the quality of the manuscript and I hope that our responses to the reviewers’ comments have been sufficient to justify the publication of our manuscript in PLOS ONE. Sincerely, Jake Daykin School of Physics and Astronomy University of Southampton Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0289223.r002
14 Jul 2023 Decision Letter - Xuejian Wu, Editor Bi-frequency operation in a membrane external-cavity surface-emitting laser PONE-D-23-16239R1 Dear Dr. Daykin, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Xuejian Wu, Ph.D. Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0289223.r003
Formally Accepted
19 Jul 2023 Acceptance Letter - Xuejian Wu, Editor PONE-D-23-16239R1 Bi-frequency operation in a membrane external-cavity surface-emitting laser Dear Dr. Daykin: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Xuejian Wu Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0289223.r004

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