The study of optical trapping of micrometer-sized particles started with spheres, and stretched out for non-spherical objects. Non-spherical examples of interest are micro-fabricated functional objects such as optical micro-motors and the probe of optical trap microscopes. When the object size is sufficiently larger than the wavelength of light, ray optics approach of determining the radiation pressure forces and torques acting on sphere particles is applicable even to non-spherical objects. However, non-spherical shapes generally lose the perfect geometric symmetry of spheres, requiring that not only the position but also angular orientation of the object be taken into account for complete analysis of trapping behaviors. In this paper, we propose a generalized computational method of ray optics, which determines the radiation pressure forces and torques acting on arbitrary shaped objects that are positioned off the optical axis with arbitrary orientation. This model is then extended to dynamic analysis to provide time-series motional trajectories of an object upon trapping. Comparison tests of computer simulation with experimental results prove that the proposed model well predict complicated trapping behaviors of micro-fabricated objects. The first stage of the experiment is concentrated on investigating fundamental behaviors of the optical trapping and rotation for polystyrene spherical particles and arbitrary-shaped glass particles in water. Next the optical trapping is tested in air, where adhesion forces between the micro-object and substrate become significant due to van der Waal's force, electrostatic attraction force, and surface tension force. Special techniques such as of PZT vibration, air ionization and heating are studied to reduce the undersirable adhesion forces. We also investigate particle motion mechanism during PZT vibration and propose a micro-manipulator for assisting the optical trapping in order to break the adhesion and manipulate the object. To increase the optical trapping efficiency in air we propose the upward beam gradient force trap in air and it shows successful trap in air. Based on the optical trap in air we propose the optical micro-motor. Micro-rotors with shape anisotropy either on their internal or external surfaces are fabricated by optical lithography and oxygen reactive ion etching of a fluorinated polyimide layer. Trapping and rotation of the artificial micro-rotors are demonstrated using only a strongly focused diode laser beam in air. Optical trapping of micro-rotors in air is more difficult than glass spheres in air. Main reason of this fact is strong adhesion of the micro-rotor and large scattering force by high relative refractive index. To cope with the problems we suggest several methods. As another application of the optical trapping in air, we propose the optical trap microscope in air. From analysis of the optical trap microscope we can find spring constant and open loop stability condition.
