Non-destructive testing of integrated nanostructures using 3D polarization control in an optical microscope

Inhalt:
Two-dimensional investigation of the spatial orientation of a nanostructure at a surface is easily possible with polarization microscopy, while 3D measurements remain a challenging task. Here we demonstrate the extension of optical polarization microscopy to the 3D case. A simple setup for generating a three-dimensional arbitrary orientation of the polarization vector in a laser focus is reported. The key component is the superposition of a linearly and a radially polarized laser beam, which can be controlled individually both in amplitude and relative phase. We exemplify the usefulness of this setup by determining the spatial orientation of a single silver nanoantenna in threedimensional space by recording the angle-variable backscattered light intensity. The example shows the high potential of this new microscopy method for non-destructive evaluation of nano-sized objects without interfering with their microenvironment.