We demonstrate that a high degree of circular polarization can be delivered to the near field (NF) of an aperture at the apex of hollow-pyramid probes for scanning optical microscopy. This result is achieved by analyzing the dichroic properties of an annealed thin polymer film containing a chiral polyfluorene derivative, placed in close proximity to the optical probe. We also prove that the degree of circular polarization in the probe NF does not depend in a significant way on the shape of the aperture, at variance with the far-field behavior. These results demonstrate the feasibility of nano-optics applications exploiting circularly polarized NFs.
© 2009 Optical Society of America
Original Manuscript: July 24, 2009
Revised Manuscript: October 14, 2009
Manuscript Accepted: October 16, 2009
Published: November 12, 2009
Vol. 4, Iss. 13 Virtual Journal for Biomedical Optics
M. Savoini, P. Biagioni, G. Lakhwani, S. C. J. Meskers, L. Duò, and M. Finazzi, "Near-field circular polarization probed by chiral polyfluorene," Opt. Lett. 34, 3571-3573 (2009)