Conical Emission Induced by the Filamentation of Femtosecond Vortex Beams in Water

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments to Authors

・Sorry if I had missed it but was there an explanation on how the TC was changed throughout the experiments? 

・On Page 3 Experimental, the authors mention that they used a half-wave plate and Glan prism to adjust the energy to a desired value. To my understanding, the pulse energy was not altered and was set to a single value throughout the entirety of the paper? If so please adjust the wording so it is clear.

・Figure 3: Why is the light from the filaments not symmetric? Is this an experimental error? Also why are the light images seemingly at a 45 degree angle? (a-c)

・Figure 7/8 was a little difficult to understand. Please clarify what it is meant by wavelength for the x-axis of (a), they are also single digits? 

・Mentioning that a NA of 0.16 is "high" for fs laser processing may be misleading. If this is mentioning that this value is "high" compared to something sure. Also if there are any data where the lens' NA is changed, it would be appreciated here.

Comments on the Quality of English Language

Generally it is readable; however, some parts are difficult to comprehend and therefore it is recommended to be checked by a native English speaker.

Also there seems to be a type error for the x-axis of Figures 7/8. Degrees is the correct word I assume.

Please go through the paper to check if there are any other errors which may cause issues.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have submitted a manuscript in which they investigate the effective transfer of OAM (Optical Angular Momentum) in non-optical parametric processes like Supercontinuum Generation (SC) and Conical Emission when focussing Gaussian and Bessel OAM carrying femtosecond laser beams in water. Compared to optical parametric processes where the OAM is transferred to the newly generated electromagnetic waves in the investigated processes here this effect has not been observed and did finally not occur. The experiments as well as the theory of SC generation support these findings due to the presented argumentation. This could have been assumed due to the nature of SC generation but it has been definitely worth  to experimentally verify this assumption within this manuscript and to better understand the interaction of high-intensity pulses with matter. The manuscript has been well written and the structure is appropriate. There is just a minor comment on Fig 7 where the wavelength scale is incorrect. With a correction of this a publication is in any case recommended.     

Comments on the Quality of English Language

There are still few language mistakes throughout the text which can all be identified during final proof-reading.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

About summary.

Avoid using abbreviations in the abstract. It is unclear what is TC?

“We hope this work can be helpful to the understanding of interaction between the intense laser pulses and matters.” This sentence is not good  for the abstract.

Many details of the beam characteristics are not mentioned.

Analysis of the experimental data is based on the assumption of the only divergence angle effect.

Plasma plays a significant role in the filamentation process,  and the intensity distribution

Is different for both types of beams. I believe that change in the photoionization yield depending on the plasma structure may affect main conclusions of the paper.

Is it possible to mention at least the critical electron number density, and non-linear part of the refractive index  for water?

What was the range of the peak laser intensities in the paper for two beams?

What was the beam polarization?

Was it  a single filament or multiple filaments?

A semi-analytical or an approximate evaluation of the importance or non-importance of above-mentioned characteristics of the beams may change the conclusions.   

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

No further comments.

Comments on the Quality of English Language

No further comments.

Reviewer 3 Report

Comments and Suggestions for Authors

Authors answered all my questions and concerns.