This article [Opt. Eng. 48, 124601 (2009)] was originally published on 21 December 2009 with an error in Fig. 3. The correct image appears here.
The corrected manuscript was published online 28 December 2009, but Fig. 1 was incorrectly placed on page 9 of the manuscript. All versions of the article were corrected on 13 January 2010 and the article appears correctly in print.