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Second Report of the Referee -- AY11417/Chin
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The authors have satisfactorily addressed my concerns, except the
biggest one that refers to the magnitude of the extinction of the
light caused by the atom. The observed extinction is a factor of two
smaller than expected from theory. This factor of two is surprisingly
large, given the conceptual simplicity of the experiment. It is
annoying that the authors do not know about the origin of this
discrepancy. This ignorance certainly decreases the value of the
reported research and the impact of the manuscript.

What remains are measurements concerning the frequency, power and
temperature dependence of the extinction. All these measurements can
perfectly be explained by theory. It is therefore surprising that,
again, the authors can explain all features of the extinction except
its magnitude.

In the end, the general reader will get the impression that the kind
of experiments reported in the manuscript suffer from unidentified and
possibly obscure effects. This is surprising because the related but
much more sophisticated experiments with an atom inside a cavity do
not knowledge.

In summary, the paper is publishable, but the message it transports is
negative, without any clear instruction on how to improve.


reply: 
In our work we investigated the influence of the atomic temperature on
the interaction with light focused to a near diffraction-limited spot size. We
believe that we demonstrated conclusively the effect of the temperature in
experiment and theory.  
We choose to compare our results to a model which assumes an ideal lens.  We
agree with the referee that it is regrettable that our observed magnitude of
interaction does not match the expectation of this model. However, real lenses
are not ideal and we believe, as stated in the manuscript, that lens and wave
front errors are the main source for the reduced interaction. 

We made the following changes to the manuscipt to improve the readability and
to emphasise our main result, the temperature dependency. We introduce the
possibility of a reduced interaction due to aberrations earlier in the text 
and refine the following paragraphs:

description of Eq 8, page 4

"For the probe field, we use the effective interaction strength Λ eff (r) = (1
− α) Λ(r) where we evaluate the spatial dependence of the mode overlap Λ(r)
according to [13], which includes the changes of the local electric field
polarization of the probe light near the focus. In addition, we heuristically
introduce the parameter α which accounts for a reduced interaction strength
due to experimental imperfections."

caption of Figure 4b), page 4

"The temperature dependence is well reproduced by Eq. (8) with α = 0.54(1) as
a free fit parameter (red solid line, chi^2_red = 11.6). Dashed blue line is
the expected extinction for an ideal lens, Eq. (8) with α = 0."

second paragraph, page 5

"Figure 6(b) (solid red line) shows the theoretical extinction expected from
Eq. (8) with our focusing parameters using α = 0.54(1) as a free parameter.
The reduction of the extinction as a function of scattered photons is well
reproduced by the model. From Eq. (8) with α = 0.54(1), we extrapolate a
spatial overlap Λ = 5.1% for a stationary atom which is approximately 10%
larger than the interaction observed for our lowest temperatures. This
estimation provides an upper bound for the temperature effect because our
model treats the atomic motion classically and therefore does not include the
finite spread of the motional ground state. The large value of α = 0.54(1)
means we observe less interaction compared to the tight focusing theory
outlined in [13]. This reduction is likely to be caused by imperfections of
the focusing lens and deviations of the incident field from a Gaussian beam."

Conclusion, page 5

"Further improvement of the interaction strength requires a careful analysis
of the focusing lens and the application of aberration corrections to the
incident probe field."