We list clarifications and corrections to a few small errors we have found in our manuscript [1].

First, in Fig. 6 the correct numbering of the references should be as follows: Aggarwal et al. [13] and Barnes and Gettemy [12]. The numbering of the references in the text is correct.

Second, Eq. (1) gives the intensity reflected from a Fabry-Pérot interferometer in the case of perpendicular incidence. We should have stated that in this equation the reflected intensity is normalized to the intensity of the incident light.

Third, in Table 1 the diameter of the fused silica calibration sample is reported to be 6 mm. The correct value is 12 mm.

Finally, it is stated that the Pr:YLF crystal that was measured was grown by FEE. Actually, the crystal was grown by VLOC [2]. FEE [3] cut and polished it.

The authors regret the errors, which do not affect any of the results and conclusions.