Shanghai University of Technology's ultra-precision measurement technology breaks through the "blockade"
Antarctic astronomical telescopes, space gravitational wave detection devices, nanomaterials, high-end precision equipment... The processing and manufacturing of this series of key equipment all require ultra-high-precision measuring instruments to measure the various parameters of a large number of optical components. In the past, ultra-precision measurement technology has become a "bottleneck" problem that restricts the development of high-end equipment manufacturing.
Recently, the research and development of a domestically produced high-end product, the digital laser interferometer, by a joint laboratory jointly established by Professor Han Sen's team led by Academician Zhuang Songlin of the School of Optoelectronics of the University of Shanghai for Science and Technology and Suzhou Huili Instrument Co., Ltd. has been progressing smoothly. Starting from the basic principle of optical interference, this instrument integrates the wavelength of the light source for metrological traceability, digital phase shift technology, and computer technology, and innovatively realizes non-contact optical measurement with nanometer precision , filling a domestic gap .It is reported that this "key technology and instrument for ultra-high precision large-aperture absolute surface optical standard measurement" won the first prize of Shanghai Science and Technology Progress in 2023 .In response to China's demand for high-end testing instruments and technologies, the research team systematically carried out research and development on key technologies for modular laser interferometer design and application. "In simple terms, an interferometer divides the laser into two beams, irradiates them onto the device to be measured, and then merges them to produce interference, thereby accurately measuring the surface topography error of the measured object, including plane, spherical, cylindrical or aspherical surfaces," Han Sen introduced.
The project technology has broken through the classical limits of standard metrology, and proposed a large-aperture absolute surface self-calibration algorithm and an integrated small-aberration optical design method, which has increased the absolute surface measurement accuracy by 6 times compared to the national first-class flat crystal, and the highest PV value accuracy has reached λ/120 (λ=632.8nm). At the same time, the research team invented a three-point cluster PZT high-output (1000 kg class) micro-drive phase shift technology, breaking through the bottleneck of heavy-load mechanical phase shift measurement; innovatively developed an optical uniformity absolute measurement technology with an accuracy of 8*10 -7 .In addition, the research team has also developed QHL detection technology with strong anti-disturbance performance, which has solved the problem of interference of unstable measurement environment on detection data and increased the measurement repeatability accuracy by more than 10 times; it has broken through the huge limitations of absolute measurement results caused by the self-weight deformation of high-precision reference surfaces when placed horizontally, and realized absolute measurement of stress-free planes.
