[OPTICAL REVIEW Vol. 11, No. 6 (2004) 365-369]
© 2004 The Optical Society of Japan

Near Field Observation of a Refractive Index Grating and a Topographical Grating by an Optically-Trapped Gold Particle

Hiroo UKITA*, Hirotaka UEMI and Atsuhiro HIRATA

Faculty of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu-shi, Shiga 525, Japan

(Received April 21, 2004; Accepted September 3, 2004)

We observed the near field for a refractive index grating fabricated on a planar light waveguide circuit (PLC) by scanning an optically-trapped 100 nm diameter gold particle. We demonstrate that stable trapping and scanning occur with a Gaussian laser beam at the scan velocity of 1.6 μm/s and Nd:YAG laser power of 25 mW. The scattered Ar+ laser light from the gold particle is strong at high refractive indexes of the grating with periods of 1.06 μm and 0.53 μm, both by s and p polarized illumination. In addition, we observed the surface profile of the optical disk tracking groove with and without the gold particle.

Key words: near field, optical tweezers, refractive index grating, planar light waveguide circuit, PLC, gold particle, optical trapping, polarization, groove

*E-mail address: ukita@se.ritsumei.ac.jp
Currently with Matsushita Denko Corporation, Kadoma, Osaka 571, Japan.