Nano-Position Sensing Using Optically Motion-controlled Microprobe with PSD Based on Laser Trapping Technique

A position sensing microprobe has been developed which satisfies harsh requirements to establish a nano-CMM (coordinate measuring machine) proposed for measuring microparts with a target accuracy of less than 50 nm within a 10 mm cubed working volume. This paper deals with dynamic properties and position sensing accuracy of the improved microprobe system for the nano-CMM using an optically trapped probe sphere of 8.0 ^m in diameter. The probe sphere is forced to vibrate with about a hundred nanometer amplitude and high frequency based on optical radiation pressure control. It is possible to measure its dynamic motions with a higher accuracy using the newly developed optical system with a position sensing detector (PSD). It is experimentally suggested that the improved microprobe system can achieve nano-position sensing in the lateral direction.