O. Sqalli et al., Improved tip performance for scanning near-field optical microscopy by theattachment of a single gold nanoparticle, APPL PHYS L, 76(15), 2000, pp. 2134-2136
Nanometer-size optical probes are gaining increasing interest in near-field
optical microscopy. Optimization of the probe shape is still a challenging
research and development issue. Here, we propose to improve the optical pr
operties of a fiber-based probe by attachment at the tip apex of one single
gold particle of 60 nm diameter. This probe produces an enhancement of the
light throughput, both in the near and the far fields, a homogenization of
the diffracted light polarization, and a higher accuracy of the topographi
c sensitivity. In this letter, the chemical procedure for the fixation of o
ne single gold particle on the apex of a standard tip for scanning near-fie
ld microscopy is described. Far-field as well as near-field measurements wi
th this probe are performed, showing improvement of the light distribution
in excellent agreement with the theory. (C) 2000 American Institute of Phys
ics. [S0003-6951(00)05315-8].