Experimental Synthesis and Demonstration of the Twisted Laguerre–Gaussian Schell-Mode Beam

Round 1

Reviewer 1 Report

The authors experimentally implement a pseudo-mode representation of a twisted Laguerre-Gaussian Schell-model beam and study the dark hollow core disappearance on free space propagation and self-reconstruction of the generated beam obstructed by a simple obstacle in the lab. The work appears technically sound and should pique interest of the photonics community, especially the opposite twist handedness (sign) requirement for either slowing down the hollow core disappearance in free space or improved self-reconstruction. I then advise in favor of publication. As a suggested optional revision, I recommend that the authors append the introduction to include some topical recent work on twisted random beams, for instance, the work on twist-induced classical entanglement, OL, 46, 5859 (2021) and its resilience in atmospheric turbulence, JOSA A, 39, C1 (2022). 

 

Author Response

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Reviewer 2 Report

This is an interesting paper about a partially coherent beam endowed of both a vortex phase and a twist phase.

 

The authors develop a suitable modal analysis based on the hypothesis that the cross-spectral density (CSD) can be represented by a Pincherle-Goursat kernel [F. G. Tricomi, Integral Equations, Dover]. Such a hypothesis is reasonable because for any realistic CSD only a finite set of eigenvalues is significantly different from zero. The propagation properties of the studied beam as well as its self-healing properties are thoroughly examined.

 

A further point of force of the paper is the experimental realization and test of the proposed CSD. This confirms very well the theoretical predictions.

 

In summary I think that the paper gives a significant contribution to the study of partially coherent beams and should be accepted in its present form.

 

Author Response

 We thank the reviewer for the positive report.

Reviewer 3 Report

This paper deals with a new type partially coherent fields of the Gaussian Schell-model family endowed with vortex and twist phases. The experimental realization of TLGSM beams with controllable parameters via the incoherent superposition of the corresponding pseudo-modes is investigated both numerically and experimentally. The synthesized beams validate the combination effect of the twist phase and the vortex phase on the evolution properties of a partially coherent beam. The experimental result that the twist phase helps to improve the fidelity of quantifying the topological charge of a blocked partially coherent vortex beam may have novel application. In conclusion, the paper is well written and can be recommended for a publication after minor revisions.

1.       To get a better understanding, it is better to add interpretation of the letter “T” in Eq. (10).

2.       The combination of the two phases can greatly increase the amount of OAM. How can we determine the OAM carried by the beam?

Author Response

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Reviewer 4 Report

Comments for author File: Comments.pdf

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Reviewer 5 Report

The authors presented a new technique to produce the twisted Laguerre-Gaussian Schell-mode beam, where all the required pseudo modes can be encoded into a single frame of a dynamic hologram. They demonstrated the precision of the method making comparisons between experimental results and theoretical simulations. 

The manuscript presents high quality in all aspects, from the organization of the content to the quality of results. I am happy to recommend this paper for publication. 

Suggestion:

Comparing the theoretical results of figure 4 with the experimental results of figure 9, its possible to see an astigmatic effect. It will make the TLGSM mode looks more elliptical, it is clearly visible at the propagation distance z=400. This effect could be corrected by applying a small tilt in the lens L3. If the authors want to read more about how astigmatism affects the Laguerre-Gaussian mode, I will suggest two references: 

- P. Vaity, J. Banerji, and R. Singh, “Measuring the topological charge of an optical vortex by using a tilted convex lens,” Physics Letters A, vol. 377, no. 15, pp. 1154–1156, 2013.

- B. P. da Silva, D. S. Tasca, E. F. Galvão, and A. Z. Khoury, “Astigmatic tomography of orbital-angular-momentum superpositions,” Phys. Rev. A, vol. 99, p. 043820, Apr 2019.

 

Author Response

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