[OPTICAL REVIEW Vol. 13, No. 4 (2006) 266-268]
© 2006 The Optical Society of Japan

High-Contrast Imaging of Nano-Channels Using Reflection Near-Field Scanning Optical Microscope Enhanced by Optical Interference

Masaru SAKAI1, Shuji MONONOBE1, Shusaku AKIBA2, Akifumi MATSUDA2, Wakana HARA2, Mamoru YOSHIMOTO2 and Toshiharu SAIKI1,3

1Near-Field Optics Group, Kanagawa Academy of Science and Technology (KAST), KSP East-409, 3-2-1 Sakado, Takatsu-ku, Kawasaki 213-0012, Japan
2Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
3Department of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan

(Received December 29, 2005; Accepted March 8, 2006)

We demonstrated a contrast enhancement in a near-field scanning optical microscope (NSOM) by optical interference with an aperture probe in reflection (illumination-collection) mode operation. We observed a NiO film deposited on a sapphire substrate and clearly visualized 2-nm-deep nano-channel structures on the surface of the film. The reflection NSOM enhanced by optical interference is quite a promising instrument for high-resolution optical detection and estimation of low-contrast nanostructures.

Key words: near-field scanning optical microscope, illumination-collection mode, aperture probe, optical interference, high resolution imaging, high contrast imaging, nano-channel