T. Saiki et al., DIRECT OBSERVATION OF SIZE-DEPENDENT FEATURES OF THE OPTICAL NEAR-FIELD ON A SUBWAVELENGTH SPHERICAL SURFACE, Optics letters, 21(9), 1996, pp. 674-676
We investigate the characteristics of the optical near field of a subw
avelength dielectric sphere by using a nanometric fiber tip and a sens
itive technique of wavelength conversion. The decay length of the near
field induced around the single sphere is directly measured to be 0.3
of its radius, obtained by precise positioning of the probe tip. A nu
merical calculation of the optical near field based on the Mie scatter
ing theory is in good agreement with the experimental results. The enh
ancement of fluorescence collection efficiency in the near-field regio
n is also observed. (C) 1996 Optical Society of America