This thesis is focused on the precision profile measurement of surface with optically trapped micro-particles. Optical trap is trapping micro-particles by single-beam gradient force of condensed laser beam. Optically trapped particles have high resonant frequency and low spring constant. If a three-dimensionally trapped particle is used as probe, fast measurement and high resolution is expected.
However, three-dimensional trapping of a particle is hard, so a two-dimensionally trapped particle by downward beam is used. As a particle on the surface of specimens is moved for fixed laser, the backscattered light on a particle is varies. With this principle, feedback system is realized in an aqueous environment. By measurement of a saw-toothed surface, it is verified that measurement system with optically trapped particle is proper to measure oblique surface.
