Fundamental study on the new probe technique for the nano-CMM based on the laser trapping and Mirau interferometer

The nano-CMM as a coordinate measuring machine for micron-sized 3-D shapes is required to satisfy the measuring range of about a cubic centimetre and the accuracy of less than 50 nm. In order to develop such a nano-CMM, the probe with a microsphere must achieve detecting accuracy of nanometre order and a contact pressure force of less than 10 N. In this paper, a new probe technique for nano-CMM using a laser trapped microsphere is proposed. The principle of measurement based on the laser trapping technique and the microscope interferometer is presented. Computer simulations of radiation pressure force are performed to develop the laser trapping probe experimental system. Three-dimensional trapping of a microsphere is achieved. The contact position is estimated by measuring the displacement of the microsphere.