Correction to: Nature Communications https://doi.org/10.1038/s41467-018-05706-3, published online 21 August 2018.

The original version of this Article contained an error in the x-axis labels of Fig. 3a, b, which incorrectly read ‘z (mm)’. The correct version states ‘z (nm)’. This has been corrected in both the PDF and HTML versions of the Article.