We experimentally investigated the reciprocity of scanning near-field optical microscopy between illumination and collection modes. Near-field transmission images of single gold spheres and nanorods observed by the two modes are found to be equivalent to each other in the region from visible to near infrared. This result shows that reciprocity holds for the near-field scattering problems. We found that the conventional optical selection rule for far-field excitations does not apply not only under illumination mode but also with collection-mode arrangements. The possible origin of this observation might be the near-field probe.
© 2006 Optical Society of America
Original Manuscript: January 17, 2006
Revised Manuscript: February 20, 2006
Manuscript Accepted: February 26, 2006
Vol. 1, Iss. 6 Virtual Journal for Biomedical Optics
Kohei Imura and Hiromi Okamoto, "Reciprocity in scanning near-field optical microscopy: illumination and collection modes of transmission measurements," Opt. Lett. 31, 1474-1476 (2006)