Abstract

Near-field scanning optical microscopy (NSOM) using the aperture probe (AP) has helped to uncover exciting phenomena such as single molecule excitation [1], optical polarization singularities [2] and slow light [3]. However, the interpretations of these measurements have all been based on the assumption that what is collected is the in-plane electric near-field [2,3,4]. And, until the recent advent of metamaterials [5] this view has remained unchallenged. Interestingly, the AP has been recently reported yield information on the in-plane magnetic field [6]. In this study we show that contrary to both, the originally held assumption and the assertion of the new study, a typical AP (as shown in Fig. 1a) is sensitive to both electric and magnetic fields. Specifically, we show that the AP collects radiation from the four in-plane components of the near-field.

© 2013 IEEE