Normalized transmitted power versus SNOM tip position over the capsid. The calculation has been performed for the dsDNA virus (green triangles) and for empty nanocontainers with different water occupancy: 100% (blue triangles), 50% (green diamonds), 10% (red squares) and 0% (black circles). The relative position of the tip with respect to the virus capsid (represented with blue squares), for three different values of the scan direction, is shown. Inset shows the asymmetry degree in the optical signal (see text) for the empty capsid and for a container with a 50% water content.
Douas et al. Nanoscale Research Letters 2013 8:171 doi:10.1186/1556-276X-8-171