The world's first nanometer laser gauge was born in Tsinghua

What is the relationship between the subtle red light and the grand bridges, majestic high dams, and sophisticated machine tools? Nano-laser calipers are closely linked to seemingly incomprehensible: in the laser, the 1/8 - 79 nm wavelength of the red light is used as a unit to measure small changes in the size or position of the object, the bridge , high dams, and precision machining of workpieces, even if a tiny deformation or minute movement on the nanometer scale can be measured - on July 4th, after the Chinese Institute of Metrology after intense and rigorous testing The world’s first nanometer laser scales were announced. In order to turn this bizarre idea into reality, the task force led by Professor Zhang Shulian, the State Key Laboratory of Precision Measurement Technology and Instruments of Tsinghua University, fought for it for 10 years.
This is a veritable nanoscale laser ruler - within a 12mm length, any 79nm micromovement can be measured with a linearity of a few hundred thousandths. Let's make a comparison - a human hair has a diameter of 70 microns, which is more than 886 times the wavelength of red light 1/8. Although accurate, the nanometer laser gauge is quite simple in appearance and looks like it has a thin glass tube with red light and white light inside a closed 30 mm diameter quartz. In the glass tube, the quartz glass tube is only slightly longer than the palm of your hand. The magic of it is that the laser beam that emits the laser beam itself can sense the size of the external object. Once you push the measuring rod out of the cylindrical laser, it immediately tells you how much the distance has been pushed.
In addition to the large measuring range and high accuracy, another very significant advantage of the nano laser gauge is that it can calibrate its own “scale” and directly read out how much its measurement object is displaced, unlike other measurement moves. Sensors, such as capacitive displacement sensors, eddy current displacement sensors, and inductive displacement sensors, all need to be calibrated with additional instruments before they can be used for measurements.
Some domestic and foreign scientists have made attempts to evolve a laser directly into a displacement sensor. Because of the defects in the principle, it can not solve the problem of the recognition of the displacement direction, and has abandoned research in this direction.
Ten years ago, Professor Zhang Shulian first discovered the new phenomenon in the research of their own design of dual-frequency lasers: a reflection lens inside the laser moves a tiny distance, and the vibration direction of the electric field of the laser's internal light changes once. . After many years of conception, it crossed the fields of laser technology and metrology, turning these phenomena into inventions: Counting the number of changes in the direction of the electric field's vibration to determine the size of the mover's movement. At the same time, they also developed a set of mature implementation technologies. The two invention patents related to this technology have been authorized by China.
Professor Zhang Shulian said: “This invention can be widely used in thermal expansion coefficient, displacement measurement of mechanical parts and components, calibration of gauge blocks, deformation measurement of bridges, dams, and buildings. In the future, it may largely replace the current Widely used inductive micrometers.” He also mentioned that there may be a small number of nanometer laser gauges available for research and industrial use in the near future.