This article [Opt. Eng. 55(8), 081302 (2016)] was originally published on 20 November 2015 without an Acknowledgments section. The following Acknowledgment was added:
This work was funded by Government Assignment No. 3.109.2014/K of the Ministry of Education and Science of the Russian Federation. A.P.L. and E.V.U. thank the Ministry of Education and Science of the Russian Federation for support via the Scholarships of the President of the Russian Federation for Young Scientists and Graduate Students.
The paper was corrected online on 15 July 2016. It appears correctly in print.