We have developed a scanning near-field optical microscope with an optically trapped metallic particle that has a small diameter compared to the wavelength of visible light. In this microscope we employed spot illumination to enhance the intensity of light scattered from a probe particle so we could reduce the diameter of the probe particle to 40nm. We detected slight irregularities of the surface of the cover glass near 10-nm depth. Also, we observed gold colloidal particles on the surface of the cover glass.
© 1997 Optical Society of America
Tadao Sugiura, Takao Okada, Yasushi Inouye, Osamu Nakamura, and Satoshi Kawata, "Gold-bead scanning near-field optical microscope with laser-force position control," Opt. Lett. 22, 1663-1665 (1997)