High-Performance NIR Laser-Beam Shaping and Materials Processing at 350 W with a Spatial Light Modulator

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper, the authors presented detailed measurements of phase response of a cooled SLM under average laser power over 300 W, the observed thermal response, the comparative numerical modelling and experimental results of efficient multi-beam and shaped beam processing on metals with average power up to P = 350W. Overall, the manuscript was well organized with systematic experimental results and discussions provided. The manuscript can be accepted after addressing the following concerns.

1. Some sentences are hard to follow and need to be modified, e.g.,

Page 3: “To enable all these applications, thorough characterization of the optical and thermal response of LC-SLM and its constituent materials to laser irradiation are required and how these significant improvements in power handling relate to workpiece materials modification capabilities.”

Page 3: “A Spiricon CCD camera was placed behind the turning mirror M5 and this low intensity transmitted beam reflected from M6 to the CCD, placed near the focal plane of L5.”

2. Scale bars in Figs 11 and 13 are hard to read and need to be modified.
3. “273 W” was marked in Fig. 7e. However, in the caption of Fig. 7e, the value is 327 W.
4. Also in the caption of Fig. 7e, there are two “P(T)” in the last sentence.
5. Further explanations for the mechanisms causing the distribution of Fe and Mn shown in Fig. 14 should be provided. Besides, the elemental labels in Fig. 14b-e should be enlarged.
6. In Fig. 15d, the Oxygen concentration was higher in the Spectrum 1 than Spectrum 2. However, in the caption of Fig.15, it was stated that “the outer ring (Spectrum 2) has a higher Oxygen concentration”.

Author Response

Please see the attachment which addresses every point made by the Reviewer

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript introduces an a new SLM device with high first order diffraction efficiency，which enables the device to be used at an average power of more than 350W, and the authors also conducted a high-power laser processing verification experiment. Overall, the article is substantial, the experimental data is reliable, and it has certain significance for high-power SLM devices. So, it is recommended to be accepted after minor revisions.

Additionally, I have some questions:

1. I understand the authors' main innovation lies in implementing a highly reflective dielectric coating near the CMOS backplane in the LC-SLM section to reduce thermal absorption in the SLM, thereby increasing the device's maximum power tolerance. Is this correct? Are there other potential factors that could further enhance thermal performance? For instance, could adjusting the thickness of the sapphire window or using alternative window materials with superior thermal properties?
2. In Figure 7, the curve at φ < 0.5π shows no deviation at 20W laser power, but deviations emerge when power exceeds 50W. Does this indicate that power levels above 50W begin to affect the SLM's low-phase-shift performance?
3. The "250W" labeling in Figure 5(g) appears inappropriate, as the figure does not represent a single power curve.
4. There appears to be a discrepancy between the statement "A deviation from a linear response is already evident at 200W below φ = 0.5π while at 327W and 383W..." and the 273W annotation in Figure 7.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Review has been added as word file.

Comments for author File: Comments.pdf

Author Response

Please see attachment

Author Response File: Author Response.docx