We present an experimental study of near-field optical interactions between
an optical probe and sample objects with different dielectric properties.
The interaction strongly affects the radiation emitted at angles beyond the
critical angle of total internal reflection in the substrate (the forbidde
n light regime). Such an effect has been predicted theoretically. Our exper
imental data show that if a conducting object is close to the optical probe
, p-polarized optical fields are deflected away from the object. On the oth
er hand, s-polarized fields are deflected toward dielectric objects. The ex
perimental results show good qualitative agreement with numerical simulatio
ns. The described effects have a strong influence on image formation in sca
nning near-field optical microscopy and thus have to be taken into account
for image analysis. (C) 1999 Optical Society of America [S0740-3232(99)0220
1-2].