Theoretical and Experimental Study of Optimization of Polarization Spectroscopy for the D2 Closed Transition Line of 87Rb Atoms
Round 1
Reviewer 1 Report
Referee report on the manuscript ‘Theoretical and Experimental Study of Optimization of Polarization Spectroscopy for the D2 Closed Transition Line of 87Rb Atoms’
by Jeong, J.Y.; Lee, S.L; Hwang, S.G; Baek, J.U; Noh, H.R; Moon, G.
The authors report on their studies of the method of polarization spectroscopy. This method is one of several ways to stabilize the frequency of a laser system to an atomic or molecular transition. Such a stabilization is required in many laser experiments in different fields of science and metrology. Polarization spectroscopy has the advantage of a comparably simple experimental setup and that it gives directly a dispersion-like signal as required for stabilization of a laser frequency. The authors have experimentally and theoretically investigated the spectral line shapes and frequency uncertainty as a function of pump beam intensity and temperature. They used three different theoretical models to interpret the experimental spectra and were able to identify one specific model, which includes coherence effects, reproducing the experimental data in an optimal way. The authors found ranges of the pump beam intensity and temperature where the spectral line shape does not depend on those parameters to first order. The paper is clearly written, gives valuable information on theoretical as well as experimental aspects of their investigations of polarization spectroscopy and fits well into the scope of the journal Applied Sciences. I believe the paper will be interesting to many groups working with polarization spectroscopy or other spectroscopy methods and can help them optimizing their setups. Also the detailed description of the different theoretical models can be useful to the readers working in the field to get a deeper understanding of observed line shapes. Altogether, I want to recommend this manuscript for publication in Applied Sciences with the following suggestions for minor changes.
Here I have some suggestions for minor changes:
- line 22, ‘Recently’: The authors refer to a publication in the year 2013 which is not really ‘recently’.
- Equ. 1: I have some doubts concerning the consistency of units. The left side has the unit of an inverse frequency. The right side has the unit of frequency. The authors may check this equation.
- lines 60+61, ‘…including the coherences connected via interactions not greater than three photons.’: I think it should read: ‘interactions with not more than three photons’. Also I believe this process of multiphoton interactions should be explained in more detail to the reader by one or two more sentences.
-line 64: replace ‘calculated methods’ by ’calculation methods’.
- line 80+81, ‘the Rabi frequency of the probe beam’: It is not the probe beam which has a Rabi frequency. Rather the atom has a Rabi frequency in the presence of the probe beam.
- line 123, ‘results agree very well’: The agreement between experiment and theory is not so very good in Fig. 3 c) and f). The authors may give some explanation concerning this point.
- line 136, ‘e 4 shows the experimental…’: There must be some typo at the beginning of this sentence.
- Fig. 5: ‘Experiment’ and ‘Theory’ should be indicated in the diagrams for better reading, not only in the figure caption.
- Fig. 5, figure caption: Replace ‘The unit of frequency uncertainty has an arbitrary unit.’ by ‘The frequency uncertainty has an arbitrary unit.
End of referee report
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
I am surprised not to find the manuscript title in the headlines of the manuscript pdf file.
The optimization of light beams for frequency/wavelength, polarization, cross section, power, and whatever other parameters is a recurring problem in any such work.
The authors appear to have done their experiments and calculations competently. The description is appropriately detailed. The English is largely correctly phrased. However, what I am missing are enhanced lines of thought that give the text structure. The present text is a rich collection of details most of which are necessary, but not easy to read.
I suggest to the authors that they rephrase parts of their text to make it easier to read.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
