A Review of Optical Parametric Amplification at the Vulcan Laser Facility

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript focuses on the developments and application of the Optical Parametric Chirped Pulse Amplification (OPCPA). There should be three parts accroding to the main idea of the article, the benefits and drawbacks of OPCPA, developments of OPCPA technologies at the Vulcan laser, the OPCPA technology for Vulcan 20-20 upgrade.

The article achieved the goals of the first part quite well, but there are shortcomings for the the second and third parts.

For example, lines 195-216 is the entire and only introduction to the 20-20 project, which is too brief, more information about the project should be added to provide a detailed explanation of relationship between this project and past technological foundations. So as the second part.

The article is more like a review article in the OPCPA technology. It is recommended to further expand and supplement the last two parts before publication.

Author Response

Thank you for your review, please see attached for the points addressed.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors reviewed the development of the OPCPA technique and how it advances the Vulcan laser facility. This work is of interest to the high-power laser community. I recommend publishing it in Photonics, and I only have one question and a few wording suggestions.

 

1. In Figure 3, the proposed non-collinear phase-matching geometry appears to have a tiny non-collinear angle (0.42°), which requires ~50-m distance to separate two 400-mm (using the maximum crystal size listed in Table 1) beams. Could the authors comment on the practical challenges such geometry could pose to a high-power laser facility?
2. Line 58: The purpose of temporal stretching is to reduce the peak power rather than the fluence.
3. Line 81: Should LIDT stand for laser-induced damage threshold?
4. Line 109: Please consistently use either Ti:Sapph or Ti:Sapphire across the main text.

Author Response

Thank you for your review, please see attached for the points addressed.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Petawatt level lasers have great applications in the field of laser driven particle acceleration, plasma physics and laboratory astrophysics etc, and OPCPA is one of efficient ways to produce ultra high peak power lasers. This works reviewed the development of high peak power lasers by OPCPA in Central Laser Facility (CLF). This work also compared benefits and drawbacks of three methods to generate petawatt level lasers: OPCPA, Nd:glass and Ti:sapphire. This work provided a very good insight into building a petawatt level laser. I recommend accepting this work to be published in Photonics. However there are a few blemishes requiring authors to improve:

1、 The full name should be given at the first appearance of “OPCPA” at line 10, while only abbreviation should be given in line 61-62.

2、 More detailed descriptions should be given in the caption of Fig. 1. Red squares represent Nd：galss, yellow diamonds represent OPCPA, ……., solid lines represent ……, dashed lines represent ….

3、 In Table 1, numbers in the last column were incorrect.  λ₀，Δλ（nm），corrected values 880, 350 for BBO,… 810, 100 for YCOB etc.

Author Response

Thank you for your review, please see attached for the points addressed.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

 

1) The authors emphasized that phase-matching in DKDP at pumping by second harmonics of an Nd laser is a key point of OPCPA at Vulcan and over the world. However, they ignored the paper [1] where Lozhkarev et.al in 2005 discovered ultra-broadband phase-matching in DKDP. In fact, this paper disclosed DKDP as a best candidate for OPCPA for high power pulses. The precise Sellmeier equations which include the dependence on the deuteration level were found, theoretically analyzed and experimentally confirmed. 

Was Fig.3 of the present manuscript plotted using the Sellmeier equations from [1]? If so, the authors should mention it. If other Sellmeier equations were used, the authors should at least compare the spectra obtained using different Sellmeier equations. The corresponding corrections in Table.1 should be made.  

 

Actually, the OPCPA in DKDP at pumping by second harmonics of an Nd laser was proposed in 2004 in [2] (also not cited in the manuscript ) but detail physical consideration of this idea was undertaken  in  [1].

 

2) Other corrections in the references are the following:

2.1)“The highest achievable peak power then escalated: 3.67 TW in 2002 [6], 16.7 TW in 2003 [7], 350 TW in 2005 [8], 560 TW in 2007 [9], and 1 PW in 2009 [10].”  

 

should  be replaced by 

“The highest achievable peak power then escalated: 3.67 TW in 2002 [6], 16.7 TW in 2003 [7], 100 TW in 2005 [3], 350 TW in  2006 [8], 560 TW in 2007 [9], and 1 PW in 2009 [10].”

[3] - see below 

2.2) “in various facilities allowing 10s and even up to 100s PW [30–33]” 

Reference to the Japanese Projects [4-8] should be added here.

 

3) The acme point of the manuscript is the Vulcan 20-20 facility. There is no reference to it in the list of references, which means that the manuscript is the first publication about Vulcan 20-20. The authors give a very short (two paragraphs) description. Much more detailed information about it should be included in the manuscript. Parameters and features of the Vulcan 20-20 laser design should be described in more detail.  Comparison of the Vulcan 20-20 laser with other 10s and even up to 100s PW projects based on the OPCPA in DKDP (SEL-100PW, EP-OPAL, XCELS, Gekko-EXA) should be given.

 

 

 

1.             V. V. Lozhkarev, G. I. Freidman, V. N. Ginzburg, E. A. Khazanov, О. V. Palashov, A. M. Sergeev, and I. V. Yakovlev, "Study of broadband optical parametric chirped pulse amplification in a DKDP crystal pumped by the second harmonic of a Nd:YLF laser", Laser Physics 15, 1319-1333 (2005) 

2.             N. F. Andreev, V. I. Bespalov, V. I. Bredikhin, S. G. Garanin, V. N. Ginzburg, K. L. Dvorkin, E. V. Katin, A. I. Korytin, V. V. Lozhkarev, O. V. Palashov, N. N. Rukavishnikov, A. M. Sergeev, S. A. Sukharev, G. I. Freidman, E. A. Khazanov, and I. V. Yakovlev, "New scheme of a petawatt laser based on nondegenerate parametric amplification of chirped pulses in DKDP crystals", JETP Lett. 79, 144-147 (2004) 

3.             V. V. Lozhkarev, S. G. Garanin, R. R. Gerke, V. N. Ginzburg, E. V. Katin, A. V. Kirsanov, G. A. Luchinin, A. N. Mal'shakov, M. A. Martyanov, O. V. Palashov, A. K. Poteomkin, N. N. Rukavishnikov, A. M. Sergeev, S. A. Sukharev, E. A. Khazanov, G. I. Freidman, A. V. Charukhchev, A. A. Shaykin, and I. V. Yakovlev, "100-TW femtosecond laser based on parametric amplification", JETP Lett. 82, 178-180 (2005) 

4.             J. Kawanaka, K. Tsubakimoto, H. Yoshida, K. Fujioka, Y. Fujimoto, S. Tokita, T. Jitsuno, N. Miyanaga, and G.-E. D. Team, "Conceptual design of sub-exa-watt system by using optical parametric chirped pulse amplification", Journal of Physics: Conference Series 688, 012044 (2016) 10.1088/1742-6596/688/1/012044.

5.             J. KAWANAKA, H. YOSHIDA, K. TSUBAKIMOTO, K. FUJIOKA, H. MURAKAMI, Y. FUJIMOTO, N. MIYANAGA, and H. AZECHI, "Conceptual Design of a Sub-Exa-Watts Laser System “GEKKO-EXA”", The Review of Laser Engineering 42, 179 (2014) 

6.             Z. Li and J. Kawanaka, "Laser Technique Improvement for Exawatt-Class Peak-Power in Japan", Review of Laser Engineering 49, 101-105 (2021) 

7.             Z. Li and J. Kawanaka, "Possible method for a single-cycle 100 petawatt laser with wide-angle non-collinear optical parametric chirped pulse amplification", OSA Continuum 2, 1125-1137 (2019) 

8.             Z. Li, Y. Kato, and J. Kawanaka, "Simulating an ultra-broadband concept for Exawatt-class lasers", Scientific Reports 11, 151 (2021) https://doi.org/10.1038/s41598-020-80435-6.

 

Author Response

Thank you for your review, please see attached for the points addressed.

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Author took into account all my comments. The only point authors forgot is to update the Table 1 by DKDP data from [41]. After it the manuscript may be published.

Author Response

Dear Reviewer,
The reference [41] has been included in the table for 95%, however 70% is not in [41]. Article [69] references [41] and was used as a comprehensive study on the deuteration levels.
Please let me know if this is OK.
Best regards,
Samuel