This Letter reports the experimental observation of light confinement
effects by near-held optical microscopy. Depolarization effects giving
rise to light confinement close to nanoscopic objects have been unamb
iguously observed in near-held optical images of subwavelength dielect
ric pads etched on a flat glass substrate. According to the incident p
olarization, this phenomenon leads to reverse contrasts in the near-he
ld optical image of the same subwavelength objects.