In daily life, people are used to use a variety of schlieren instrument tool to measure the object of different length, 4.588 km long nanjing Yangtze river bridge, 2.26 meters height of yao Ming, 4.25 mm narrow bezel iPhone6...These are the direct perception of the length of the human eye can, but how to measure the length of those who can't see?How to define the thickness of one percent human hair?For a century before, these problems have been a man named Albert Abraham · Michelson scientists solved.In 1883, Michelson in order to study the famous "ether" problem, using light interference characteristics, design and invented the first Michelson interferometer.Principle is very simple, it will be a beam of light into two beams, after the same distance communication in the two beams of light together, then you will see in some places light stripe, which is the sum of the strength of the two beams of light intensity, but also find some places observed dark stripes, namely a 1 + 1 = 0, there is no strength, thus formed the pattern of stripes, when one of the beam propagation distance changes, stripe pattern will change, when the difference of two beams of light propagation distance at a wavelength of light, pattern is a change, so that it can be wavelengths of light to measure the length of the object.Different color of light wavelengths are not the same, the red light wavelengths of about 625 nm, is roughly one percent of the thickness of a human hair, and green light wavelength is 520 nm, blue light wavelength is about 470 nm.Using the wavelength of the light to measure the length of the object or object movement distance, it is the beginning of optical precision machinery lines shadow instrument.Later, Michelson to use its own design interferometer for stored in schaeffler (Sevres) international standard metric scale measure, determine the Paris metric scale 1 to 1553163.5 the wavelength of cadmium red line length, this is not the man for the first time a and don't destroy the length of the benchmark, so accurate measuring the Michelson is famous worldwide.
Michelson interferometer with simple structure, high precision, thus is widely used in various fields.In 1920, astronomers Michelson and f. g. pease cooperation, put a 20-foot interferometer in 100 inches behind the reflecting telescope, made the first stellar interferometer, and use it to measure the Orion alpha (betelgeuse) angular diameter, calculate the diameter is about 3.86 x 108 km, about 30000 earth so big, cause the attention of the scientific community and the media.At the same time it can be made into a seismometer, using artificial seismic wave, the detection of oil and gas deposits;Can be made into optical coherence tomographic imaging, scanning fundus morphology, which is used to detect glaucoma, cataract and other eye diseases;Even our smart phones in the hands of a screen, schlieren apparatus can also be used to test the flatness.In 1907, Michelson "invention of precision optical instruments and applications of these instruments spectroscopy and metrology research" won the Nobel Prize for physics, he has done the experiment is famous for its exquisite design, high precision, even Einstein also could not help but praise him for "artist" in the science.(source: the Chinese academy of sciences, Shanghai institute of optical precision machinery, author: Pan Liuhua)
