Dispersion of the Retardation of a Photoelastic Modulator
Round 1
Reviewer 1 Report
In this article, Wang et al, demonstrated a method to accurately calibrate the photoelastic modulators though carefully investigating the retardation. This work is carefully done, and the presentation of the results is also fine. This work is publishable in the journal of applied sciences. There are some issues still need to be address.
The authors claimed that this manuscript includes theoretical work. However, what I have read in this article is just some line/curve fitting and no modelling, simulation or computational work is included. In general, when talking about theoretical, it means modeling, simulation or computational. Establishing equations is not generally considered as theoretical work.
In the abstract and also the discussion part, the authors mention that the calibration and the measurements are very similar. What does the authors mean by calibration here? It is extremely confusing. Do they mean the measurements taken before and after calibration? Do they mean measurements and hypothetical values?
None scientific comments.
1. It is not professional to put picture of the experiment set up in the main manuscript; they are ok if in the supplementary information. Instead, the authors should consider using simple cartoon sketch to demonstrate the experimental set up.
2. Combine Figure a,b,c into one figure rather than making them separated ones.
Author Response
We consider that your comments are quite valuable. Some corrections and additions are made as below:
1.Comment: The authors claimed that this manuscript includes theoretical work. However, what I have read in this article is just some line/curve fitting and no modelling, simulation or computational work is included. In general, when talking about theoretical, it means modeling, simulation or computational. Establishing equations is not generally considered as theoretical work.
Reply: According to this suggestion, the “theoretical” words in the revised version are deleted or replaced.
(Please refer to the revised version on line 18-19, 66-68, 70, 247-248 ) “In this report, the dispersion of the retardation of the PEM was studied.”(line 18-19), ”we present the principle analysis of the dispersion of the PEM and experimentally explore the effect attributed to the dispersion on the calibration of the PEM retardation”(lines 66-68), “Principle analysis of the dispersion of the PEM”(line 70) , ” In summary, experimental studies have been carried out on the dispersion of the retardation amplitude of a PEM.”(lines 247-248) .
2.Comment: In the abstract and also the discussion part, the authors mention that the calibration and the measurements are very similar. What does the authors mean by calibration here? It is extremely confusing. Do they mean the measurements taken before and after calibration? Do they mean measurements and hypothetical values?
Reply: In the abstract and discussion part, the calibration present the calibration values of PEM retardation amplitude, and the measurement present the actual measurement values of PEM retardation amplitude. In order to eliminate the confusions, some corrections and additions on the “calibration” and “measurement” are made.
(Please refer to the abstract in Page 1 in the revised version on line 25-26) “The results show that the relative deviation between the calibration and actual measurement values of PEM retardation amplitude are less than 1%.”
(Please refer to the discussion in Page 8 in the revised version on lines 214-218, 231-234, 241-243) ”The calibration method can be determined as follows: (i) First, for the calibration of the dispersion term, can be defined by using the Sellmeier equation describing the refractive index of the photoelastic crystal under the incident light wavelength, as illustrated in Figure 5(a); (ii) then, the driving term, can be calibrated by obtaining the retardation amplitudes of the PEM at different driving voltages applied on single wavelength incident light. “ (lines 214-218); “The calibration curve is shown in Figure 6(b). The light source was changed back to the monochromator, the PEM retardation amplitudes were also measured for the incident light wavelength in the range of 0.4－0.8mm, and the actual measurement values are also recorded in Figure 6(b).”(lines 231-234); “As can be seen in Figure 6(b), the actual measured values of are in good agreement with the calibration values. The calibration results show that the deviation between the calibration values and the measurement values,”(lines 241-243).
3.Comment:
(1). It is not professional to put picture of the experiment set up in the main manuscript; they are ok if in the supplementary information. Instead, the authors should consider using simple cartoon sketch to demonstrate the experimental set up.
(2). Combine Figure a,b,c into one figure rather than making them separated ones.
Reply: According to this suggestion, we using a schematic diagram to replace the picture of the experiment set up in the revision. However, to carefully and neatly make type setting, the Figures (a),(b) and (c) in Figures 3-6 weren’t combined in one, we hope to have your understanding.
(Please refer to Figure 2 in page 4 in the revised version on line 133-134).
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We have seriously considered all the issues and made correction according to all the reviewers’ comments. If there are any questions with the manuscript, please inform us and we wish further discussion. We hope that the revised manuscript will be suitable for publication in Applied Science.
Yours sincerely,
Dr. Shuang Wang , Kewu Li, et al.
Reviewer 2 Report
This manuscript describes a method for accurate calibration of the retardation of the photoelastic modulator. Overall, it reads well. The manuscript can be considered for publication after minor changes.
1. In the introduction, please provide more details about the principle of operation of PEM. The authors talked about the advantages of PEM (first paragraph) and then the calibration issues (2nd paragraph), but without explaining the mechanism of PEM, which makes it difficult to understand the following discussion.
2. Figure 2. The blue dashed lines are confusing. What is the purpose of the blue dashed lines? I would suggest using a schematic diagram to show the experimental setup and the light path, instead of showing a photograph. It would be nice to show a photograph of the PEM device itself.
3. Table1 and line 204, make sure to format the power (-4) as superscript.
Author Response
We earnestly appreciate your comments and suggestions. Some corrections and additions are made as below:
1. Comment: The authors talked about the advantages of PEM (first paragraph) and then the calibration issues (2nd paragraph), but without explaining the mechanism of PEM, which makes it difficult to understand the following discussion.
Reply: According to this suggestion, to make it easy to understand the following discussion, we add information on the mechanism of PEM in the first paragraph.
(Please refer to the introduction in Page 1 in the revised version on line 34-39 ) “the piezoelectric actuator excites and maintains the mechanical vibration in the photoelastic crystal when a sinusoidal driving voltage is applied, which typically forms a stress standing wave and results in a periodic variation of birefringence in the photoelastic crystal, and thus the phase and polarization states of the incident light are modulated by the temporal modulation birefringence. The PEM retarder is similar to a waveplate with fixed retardation axis and sinusoidally varying retardation values.”
2. Comment: Figure 2. The blue dashed lines are confusing. What is the purpose of the blue dashed lines? I would suggest using a schematic diagram to show the experimental setup and the light path, instead of showing a photograph. It would be nice to show a photograph of the PEM device itself.
Reply: According to this suggestion, to eliminate the confusion, a schematic diagram was used to show the experimental setup, and the PEM device was also demonstrated by an inset.
(Please refer to Figure 2 in Page 4 in the revised version on line 133-134)
3. Comment: Table1 and line 204, make sure to format the power (-4) as superscript.
Reply: According to this suggestion, the power (-4) has been formatted as superscript.
(Please refer to Table 1 Page 8 in revised version on line 207 ).
______________________________________________
We have seriously considered all the issues and made correction according to all the reviewers’ comments. If there are any questions with the manuscript, please inform us and we wish further discussion. We hope that the revised manuscript will be suitable for publication in Applied Science.
Yours sincerely,
Dr. Shuang Wang, Kewu Li, et al.
