Optical measurement technology of nano-scale displacement

• Main Authors: Liu Xiaomin, Wu Yu, Zhang Ye, Yang Guoguang
• Format: Conference Proceeding
• Language: English
• Subjects: Laser accessories and instrumentation; Metrological applications of lasers; Micro-optical devices and technology; Micromechanical devices and systems; Optical lenses and mirrors; Signal processing and detection; Spatial variables measurement
• DOI: 10.1049/cp:20060782

A novel nano-degree micro-displacement measurement based on the optical lever principle and a micro-displacement measuring device with high-precision are introduced in this article. Traditional optical lever method for micro-displacement measurement is further investigated and improved. A pair of plane mirrors, one of which is movable and the other is fixed, are adopted instead of a single one in conventional optical-lever systems. The micro-displacement generated by the object is magnified by the improved optical-lever and results in corresponding displacement of the light point on the PSD (position sensitive detector), which can be examined by a signal processing circuit. The amplification coefficient of this improved optical lever can reach 102~103 times, combined with a high resolving power to 10-10 m. A new laser measure system, whose theoretical resolution is 4 nm and less than 10 nm in practical experiment, is developed using this method. The validity of this method is proved by practical experiments. The structure of the measuring device, having the advantages of miniaturization, good anti-interface ability and high reliability, can be integrated on a silicon slice with the technology of micro-optics and MEMS and further be made into a new-type high-precision micro-optical micro-displacement sensor.